SHINE 2016 Sessions

Click on links to view session descriptions below.
1. Particle Acceleration and Wave Generation Across Scales: From Reconnection to Shocks
2. Understanding the Origin and Transport of GLEs with Modern Observations
3. Coronal magnetic field in the context of the spatial and temporal behavior of SEP events
4. Remote-Sensing Observing Techniques for Improving Space-Weather Science and Forecasting
5. The Magnetic Structure of Coronal Mass Ejections – Flux Rope Coronal Mass Ejections
6. Flux-Rope CMEs: Predicting Bz
7. Outstanding Challenges in Understanding the Heating of the Solar Corona and Solar Wind
8. Why is the slow solar wind so variable?
9. Kinetic Range Physics in the Solar Wind: Turbulence and Waves with Implications for the Turbulent Dissipation Challenge
10. The Connection Between Magnetic Reconnection and Turbulence in Collisionless Plasmas
11. Evolution and Influences of Plasma Turbulence in the Heliosphere
12. Observational Signatures and Modeling of Intermittent Reconnection in the Solar Corona
13. Heliosphere as Revealed from IBEX and Voyager Measurements
14.The Topology of Coronal Magnetic Fields
15. The magnetic nature of Solar Filaments
16. Coronal Model Drivers: a fistful of maps
17. The impact of high-resolution solar observations on understanding in situ measurements in the inner heliosphere
18. Science from the Solar Eclipse 2017
19. The Origin of Non-Eruptive Large Flares


1. Particle Acceleration and Wave Generation Across Scales: From Reconnection to Shocks

Elena Provornikova (NRL/UCAR), Carrie Black (NASA GSFC/UMBC),
Kamen Kozarev (Smithsonian Astrophysical Observatory), Joel Dahlin (University of Maryland)


Session Description

Particle acceleration by shocks and waves occurs across the heliosphere and across a large range of energies, from highly relativistic flare particles to particles energized to heat the solar corona. Many large-intensity solar energetic particle (SEP) events produced at CME shocks reveal enhanced 3He/4He ratio and heavy element abundances. These signatures are typical for flare-associated SEP events but not expected in the shock acceleration. This indicates that acceleration in flares contributes to these CME-associated SEP events. The relative role of the CME shock acceleration and acceleration mechanisms in flares still remains under debate.

Reconnection is the key process of flares, which enables different acceleration mechanisms operating at different scales. A “termination” shock formed in the super-magnetosonic reconnection outflow striking the dense loops is a potential efficient particle accelerator. Waves scattering particles across the termination shock can be produced by the reconnection process, eliminating the need for super-Alfvenic particles to excite waves. Understanding particle acceleration at flare termination shocks and large scale CME shocks may provide insight into how observed particles gain their energy and explain abundance variations. In this session, we propose to address the similarities and differences in these mechanisms, in what parameter regimes they occur, what is the observational evidence, and how they compare with simulations. We invite studies exploring shock-related acceleration mechanisms in flares and CMEs, the particle injection problem, wave generation in reconnection and observational evidence of these processes.

Questions to be addressed:

  1. How does acceleration at shocks associated with reconnection differ from acceleration at CME shocks?
  2. What are the properties of CME-driven shocks and shocks in reconnection regions as inferred from observations and simulations?
  3. What are the signatures in the energy distributions and how close/far are we from being able to reproduce them?
  4. What kinds of observations may give us coronal particle distributions?
  5. Can shocks in reconnection outflows be a source of suprathermal particles required for SEP acceleration at CME shocks?

TOP


2. Understanding the Origin and Transport of GLEs with Modern Observations
Eric Christian, Jim Ryan, Georgia deNolfo, and Gen Li

Sessions Description

How the highest energy solar energetic particles, the so called Ground Level Enhancements (GLEs) are accelerated to GeV energies remains a mystery. Both acceleration through flare reconnection and CME-driven shocks are plausible, but the question remains as to their relative importance in driving the highest energy SEP events. While these high-energy particles often reach near Earth with minimal transport effects compared to the widely studied low-energy SEPs, the spectral shape, anisotropy, and time-evolution of GLEs suggest that transport is important in interpreting these events. This session will focus on the origin and transport of the highest energy (>100 MeV) particles in SEP events, with a focus on GLEs and high-energy SEP events that may fail to register in neutron monitors, the so-called sub-GLEs (e.g. Jan 6 2014, Jan 27 2012).

Solar cycle 24 has provided an unprecedented view of GLE events including the first spectral and pitch angle measurements of GLEs over a wide range in energy from PAMELA and AMS, complementing the observations of traditional ground-based instruments. In addition, multi-point observations from spacecraft at 1 AU and the STEREO spacecraft provide detailed contextual data, particularly on CME structure and evolution and potential magnetic connectivity. While solar cycle 24 brings excited new observations to shed light on the GLE process, we welcome discussions on high-energy events from previous solar cycles.

Our session will expand on the discussion from SHINE 2015, focusing on the following questions:

  • What is the spectral shape (and its evolution) over a broad energy range and how does this constrain models of acceleration? Are there spectral roll-overs, breaks?
  • Is there a relationship between the anisotropic phase and it's evolution with time and the spectral shape (and its evolution)?
  • Do all GLEs exhibit an anisotropic phase? What about sub-GLEs? Isotropy at later times appears to be universal.
    What spectral features and/or pitch angle differences do we expect between GLE events that are well-connected. such as 2012 May 17, and other events (not necessarily GLEs) originating from the eastern hemisphere, e.g., 2012 March 7?
  • Several of the GLEs in cycle 24 are associated with high-energy gamma-ray observations from Fermi/LAT. How or do the gamma-ray observations influence our understanding of GLE particle acceleration? Are the particles in the flare and those in space related, and how?

TOP


3. Coronal magnetic field in the context of the spatial and temporal behavior of SEP events
Nariaki Nitta (LMSAL), Ming Zhang (FIT), Eric Christian (NASA/GSFC), Georgia de Nolfo (NASA/GSFC)

Session Description

The five most recent SHINE workshops hosted sessions that discussed topics related to wide angular distributions of SEP events, as brought to our attention by STEREO observations. One major factor for the phenomenon may be the coronal magnetic field if the spread of particles occurs close to the Sun and without long delay with respect to the solar eruption. Energetic particles gyrate along magnetic field lines, so SEPs can be used as a tracer for the coronal and interplanetary magnetic field that connects the source to the observer. The importance of the coronal magnetic field is not limited to SEPs, but it affects a broader range of phenomena including solar wind and eruptions. Considerable efforts have been made in recent years to improve our knowledge about the coronal magnetic field, even though it is difficult to measure it directly, and any extrapolation of the photospheric field suffers from the lack of simultaneous observations of the backside and areas close to the limb (including polar regions).

The main purpose of this session is to discuss where we are in our endeavor to understand the coronal magnetic field and how to improve it with the anticipated Solar Orbiter and Solar Probe Plus missions. The questions to be discussed include:

- How reliable is the global coronal magnetic field extrapolated from the photospheric measurements using simple (non-time-dependent) approaches? How thoroughly can they be tested?

- How does the accurate knowledge of the coronal magnetic field help us understand the spatial and temporal behaviors of SEP events and thus validate the proposed models of SEP transport?

- What SEP-related observations (including high-energy flare emissions) can contribute to the validation of coronal field modeling?

TOP


4. Remote-Sensing Observing Techniques for Improving Space-Weather Science and Forecasting
Mario M. Bisi (STFC RAL Space, UK), Bernard V. Jackson (CASS-UCSD, USA), and David F. Webb (ISR-BC, USA)

Session Description

Various aspects of human society have become highly reliant on modern technologies and regular, uninterrupted energy supplies, many of which are at risk from extreme (and everyday) space weather. Today's space-weather forecasting enhancements are not advanced enough to meet the modern-day demands, and better remote-sensing observations are a key pathway to improving first, the science behind space weather, but also, second, the forecasting of space weather through improved modeling techniques based on the assimilation of remote-sensing observations. In particular, from the ground, radio heliophysics in all aspects of space weather is being boosted in no small part by the use of new-generation radio-telescope arrays such as the Long-Wavelength Array (LWA) in the USA, the Murchison Widefield Array (MWA) in Western Australia, and the Low-Frequency Array (LOFAR) in northern and western Europe. The goal of this session is to cover all aspects of remote-sensing observations for space weather purposes (science and forecasting) and the required modeling necessary with an emphasis on ground-based techniques addressing the following groups of questions numbered below.

1. What observations provide the most cost-effective forecasts, and are we in danger of losing some of our primary assets - both space-based and ground-based? How can we best utilize ground-based data such as from observations from a network of ground stations including interplanetary scintillation (IPS), MLSO, the Nobeyama radioheliograph, and other metric-frequency radio observations? What potential improvements or new techniques, including 'blue-skies' approaches, for improving forecasts are there that can be tested (e.g. developing techniques such as heliospheric Faraday rotation, Hanle effect coronagraphy, polarizing heliospheric imagery)?

2. To some extent many of the ground-based and new space-based imagery techniques envisioned view the heliosphere not that close-in to the Sun. Thus, to what extent do CMEs 'evolve' from the Sun to the Earth while in transit across interplanetary space, and what can we learn by the study of CME-driven interplanetary shocks and their combinations with other solar wind features, including relative to CIRs, CMEs, sheaths, and multistep/multi-dip storms at Earth? The study of shock sheaths needs careful attention, e.g. via the SMEI and STEREO SECCHI image pipelines.

3. For operational purposes, is visible-/white-light imaging from a platform away from the Sun-Earth line (e.g. from L5) more advantageous than imaging along the Sun-Earth line? What about imaging from both vantage points? What about radio 'imaging' from the ground (e.g. IPS, and heliospheric Faraday rotation)?

TOP


5. The Magnetic Structure of Coronal Mass Ejections – Flux Rope Coronal Mass Ejections
Mark Linton and Jon Linker

Session Description

Understanding the magnetic structure, orientation, and evolution of coronal mass ejections (CMEs) is an important goal for achieving space weather predictions. While CMEs are often complex magnetically and dynamically, significant advances have been made in understanding their nature by assuming that many CMEs have a coherent magnetic flux rope structure. Mapping remote sensing observations of CMEs to magnetic flux ropes, and modeling in situ measurements of interplanetary CMEs as magnetic flux ropes give powerful methods for interpreting and measuring characteristics of CMEs, and for predicting their evolution as they propagate through interplanetary space. To move forward in our understanding of CME structure and evolution, it is therefore important to investigate the current capabilities and limitations of these flux rope models, as well as their future promise. With this in mind, we will explore the following questions:

  1. What evidence do observations and simulations show for and against a flux rope structure in CMEs during their eruption and during their propagation through interplanetary space?
  2. What observations can be made to constrain the morphology, orientation, and magnetic field structure of flux rope models of CMEs?
  3. What are the prospects for using observationally constrained flux rope models to predict the trajectory and magnetic field structure of CMEs during their eruption and propagation through interplanetary space?

TOP


6. Flux-Rope CMEs: Predicting Bz
Pete Riley, Chris Russell

Session Description

An accurate prediction of the interplanetary magnetic field, and, in particular, its z-component (Bz) is a crucial capability for any space weather forecasting system, and yet, thus far, it has remained largely elusive (a point exemplified by the fact that no prediction center currently provides a forecast for Bz). In this working group session, we will discuss: (1) Various physical processes that can produce non-zero values of Bz; (2) Candidate approaches (both statistical and mechanistic) that may ultimately lead to reliable forecasts of Bz; and (3) Possible limitations and intrinsic uncertainties in its estimate. Additionally, we will discuss predictions of other solar wind parameters, particularly the bulk plasma speed. The session will be discussion-oriented, but we encourage participants to bring (or send in advance) any slides necessary to make their points.   The objectives will be to: (1) Assess our current state of predictive capabilities; (2) Identify potentially useful approaches that can be investigated during the upcoming year; and (3) Foster collaborations amongst attendees to work on this topic.

TOP


7. Outstanding Challenges in Understanding the Heating of the Solar Corona and Solar Wind
Haihong Che, Nicki Viall, Marco Velli, Scott McIntosh, Bart De Pontieu

Session Description

The heating of the solar coronal and solar wind plasma are two of the most important unsolved problems in heliophysics. The two popular mechanisms most prevalent in the literature in coronal heating involve Alfven wave heating and “nanoflare” (or magnetic reconnection,) heating. Observations of non-negligible Alfven waves fluxes in both corona and solar wind suggest that Alfven waves are an important free energy source in the corona and solar wind. In addition, observations of magnetic strands with various spatial scales rooted from the photosphere suggest that the stored magnetic energy can be released by nanoflares to heat the coronal plasma.

The plasma in the corona and solar wind is nearly collisionless and the dominant energy dissipation is through wave-particle interactions on kinetic scales rather than collisions. However how Alfven waves efficiently cascade down into kinetic scales, and what kinds of wave-particle interactions are involved in the dissipation are poorly understood. Nanoflares can accelerate particles, drive many wave modes and instabilities on various scales, but it remains unclear what wave couplings and instabilities convert the magnetic energy into heat.

In the past years, driven largely by observational technology advances, progress has been made in both wave and nanoflare heating, with many new ideas and models being developed. Therefore, it is high time for a discussion between theorists and observers to communicate the latest concepts and models to take advantage of the these advanced data to constrain theories, and to better interpret observational data.

The goal of this session is to provide an active interface for communications between theorists and observers to address the following scientific questions:

1. How do Alfven waves cascade efficiently into kinetic scales and how are they dissipated? How can observational data from both the Sun and in-situ solar wind observations be used to constrain the cascade process?

2. What information can observations of nanoflares provide to help to understand the nanoflare heating and particle acceleration in both closed and open magnetic field lines?

3. Are there signatures of coronal heating processes in the solar wind? what are they and what can we learn from them?

In our 2016 meeting we will focus on the direct and indirect observational implications of Alfven wave and nanoflare heating models and relevant theoretical advances. The mainspecific theme will be: where/under what condition is collisionality in the solar corona sufficient to provide dissipation and heating? And if collisional effects are insufficient what are the possible theoretical and observational implications?

TOP


8. Why is the slow solar wind so variable?
Aleida Higginson (Michigan), Nicholeen Viall (NASA/GSFC), Ben Lynch (UC Berkeley)

Session Description

The slow solar wind is often characterized by three properties: 1) being more highly ionized than the fast wind, 2) having an elemental composition closely resembling that of the solar upper atmosphere, and 3) being variable in nature. The first two properties are defined by elemental and charge-state compositions, and limits on these compositions are used to classify the slow solar wind. The variability of the slow wind, however, has not been well defined. This is due in part to the fact that the slow solar wind exhibits large changes over a broad range of time scales ranging from hours to a solar cycle. Measurements by ACE, SOHO, Ulysses, and others, show not only that slow wind periods vary in space and time, but also that within slow wind periods, there are fluctuations in properties such as speed, composition, magnetic field, and density that are not well defined or understood. The nature of this variability contains information about the formation of the slow wind and its source regions. It is therefore important to understand how these properties can arise from wind acceleration processes and sources at the Sun, and to disentangle them from propagation effects and turbulence.

The purpose of the session would be to bring together remote observers, in situ observers, theorists, and modelers to quantify solar wind variability and to attempt to determine its origins. We propose a discussion centered on the following questions:

  • What are the timescales of slow wind variation and structure?
  • What are ways to identify the variability that is not due to turbulence or propagation, and must originate at the Sun?
  • What do they tell us about possible source regions and acceleration mechanisms at the Sun? How can slow wind variability help us constrain slow solar wind models?
  • How can Solar Orbiter and Solar Probe Plus contribute to our understanding of solar wind variability?

TOP


9. Kinetic Range Physics in the Solar Wind: Turbulence and Waves with Implications for the Turbulent Dissipation Challenge
Peter Gary, Tulasi Parashar, Chadi Salem, Daniel Verscharen, and Kris Klein

Session Description

This session will focus on kinetic range physics of plasma turbulence in the solar wind. The primary goal is to understand the nature of electromagnetic fluctuations at scales smaller than the spectral break point. Some studies have suggested that the turbulence at these scales is highly intermittent and nonlinear while others indicate that linear theory may describe some properties of fluctuations at these scales. The primary science question of the session is: "What is the common ground between the above mentioned viewpoints?" Specific questions that address the differences between nonlinear turbulence and linear waves are:

1) Can we classify the kinetic range turbulence as "strong" or "weak"? Are the fluctuations in the quasilinear or fully nonlinear regimes?
2) What properties of kinetic range fluctuations can be adequately represented by linear waves? If linear theory is useful for wave description, can the waves be classified as kinetic-Alfven-like and/or magnetosonic-whistler-like?
3) If kinetic range turbulence is a fundamentally nonlinear phenomenon, which computational models and which physical models (fluid, hybrid or kinetic) are necessary to adequately represent the physics? Can nonlinear properties such as intermittency be quantified in kinetic
turbulence?
4) What are the implications of various processes for heating of electrons, protons, and heavy ions?
5) What are the key issues in the design of critical simulations of the Challenge?

The session especially invites presentations of fully nonlinear simulation results.

TOP


10. The Connection Between Magnetic Reconnection and Turbulence in Collisionless Plasmas

Greg Howes and Jason TenBarge

Session Description

Under the weakly collisional conditions typical of heliospheric plasmas, both collisionless magnetic reconnection and kinetic turbulence play key roles in mediating the flow of energy throughout the heliosphere. Each topic represents a grand challenge problem on its own, and relatively few studies have addressed in detail the often complicated interrelationship between these two fundamental physical processes. But it is almost certain that, at least under some circumstances, the influence of each process on the other cannot be neglected. This session has two primary goals: (1) to review the current state of knowledge concerning the relation between magnetic reconnection and turbulence in weakly collisional space plasmas; and (2) to identify key questions that frame the frontier of research on the interrelationship of magnetic reconnection and turbulence.

Investigating the relationship between magnetic reconnection and turbulence is complicated because there exist at least three distinct ways in which the two processes are connected:

1) How is the physics of magnetic reconnection altered in a sea of turbulent fluctuations?

2) Does the dissipation of plasma turbulence, which is observed to occur dominantly in the vicinity of intermittent current sheets, involve magnetic reconnection?

3) How does magnetic reconnection lead to the generation of turbulent fluctuations?

Most previous investigations of the connection between magnetic reconnection and turbulence have only focused on a single one of these possible connections. At present, no theoretical framework exists for placing these various possible connections into the broader context of heliophysics research. This session aims to rectify this deficiency by bringing together experts on reconnection and turbulence to construct such a theoretical framework upon which studies of the interrelationship can be organized.

Current and upcoming space missions, such as Magnetospheric Multiscale and Solar Probe Plus, aim to develop a complete understanding of energy conversion in magnetic reconnection and to determine how the energy of plasma turbulence is dissipated, leading to plasma heating, or some other form of particle energization. Therefore, reviewing and organizing our understanding of the connection between magnetic reconnection and turbulence will contribute to the development of the theoretical underpinnings necessary to maximize the scientific return from these missions.

TOP


11. Evolution and Influences of Plasma Turbulence in the Heliosphere
Bill Matthaeus, Tulasi Parashar, and Alexandros Chapassis

Session Description

This session aims to follow up on several SHINE sessions in recent years that have focused on turbulence as a mechanism to heat the solar wind and corona. It has become increasingly clear that nonlinear effects and cascade, key elements of turbulence, have significant effects not only on heating, but also on other fundamental processes. Prominent among these are reconnection, transport and energization of suprathermal particles, amplification of magnetic fields, self-organization of magnetic structures, and turbulent mixing effect on field lines and heat transport. All of these processes may be impacted by kinetic physics, while also being influenced by large scale structure. The latter may appear in the guise of Reynolds number or system size effects, or even inverse cascade in some circumstances. This session invites presentation and discussion of this broader scope of turbulence influences, in addition to recent results relating effects of large Reynolds number on heating and dissipation. Potential applications of interest would include chromosphere, corona and solar wind, magnetosheath and potentially the outer heliosphere. Physics of interest to current space craft (e.g., MMS, Cluster, ACE, Wind, Voyager) as well as upcoming missions (Solar Orbiter, Solar Probe) and planned missions (THOR) will be of interest. The goals are to improve the plasma physics knowledge, the modeling endeavors, and observational interpretations of the heliospheric turbulence, with an eye towards broadening the discussion that has become widespread in recent years. The emphasis will include observations, theory and simulations that are relevant to connecting fluid and kinetic scales. We emphasize the following issues:

Major questions are:

• What are the effects of turbulence on large scale dynamics? Do we understand how turbulence evolves in the heliosphere? What are the unsettled questions?

• How does the large magnetofluid scale cascade interact with small scale kinetic processes? Can we understand system size effects? Are couplings local or nonlocal – in scale? – in space?

Additional refined questions include:
• What controls partitioning of energy between thermal particles, energetic particles, flows and electromagnetic fields? What controls energy partitioning between electrons, protons, and minor ions?

• How do flux tubes and current sheets evolve? What do we know about current sheet structure? What are the observational signatures of secondary island formation? Is there evidence for "hot spots" of dissipation, or can uniform plasma theories work?

• What is the significance of observed intermittency? How does this relate to classical hydrodynamic intermittemcy?

This approach supports SHINE's spirit of a research discussion oriented workshop that focuses on unsettled, provocative, and controversial issues, while also contributing to SHINE's educational goal for young researchers.

TOP


12. Observational Signatures and Modeling of Intermittent Reconnection in the Solar Corona
Silvina Guidoni (NASA/GSFC – CUA), Peter Wyper (NASA/GSFC – USRA),
Carrie Black (NASA/GSFC - UMBC), Nick Murphy (Harvard-Smithsonian Center for Astrophysics)

Session Description

Magnetic reconnection is believed to be responsible for rapid restructuring of the magnetic field in the Sun's atmosphere involving processes at multiple scales with accompanying dynamics in three dimensions. Global dynamics advect flux and set the conditions for reconnection to take place on small scales. During this change in magnetic topology, energy is released into plasma heating, particle acceleration, radiation, and bulk flows, which in turn feed back on the global dynamics. Although we have a relatively complete theoretical understanding of how coronal reconnection operates under steady conditions, recent high-quality observations show that reconnection may operate in an intermittent way in the solar corona. Blobs moving along flare current sheets, spiked high-energy emission, supra-arcade downflowing loops (SADLs), and supra-arcade downflows (SADs) are all examples of localized-in-time (or space, or both) phenomena related to reconnection. Can these observations be reconciled with theoretical modeling efforts of intermittent reconnection?

This session follows on from last year's session "Challenges in understanding 3D magnetic reconnection in observations and simulations", by discussing recent progress and new challenges in understanding of intermittency in reconnection. The discussion will start from the following questions:

What solar corona observations show intermittency?
How can we characterize 3D reconnection from these observations? What drives the intermittency in reconnection?
What are the roles of ideal and resistive instabilities?
Is all solar coronal reconnection intermittent? Why or why not?

TOP


13. Heliosphere as Revealed from IBEX and Voyager Measurements
Nicholai Pogorelov, Merav Opher, and George Gloeckler

Session Description

In situ observations by Voyager 1 and Voyager 2, combined with the heliosheath tomography using energetic neutral hydrogen fluxes measured by the Interstellar Boundary Explorer (IBEX) in different energy bands gives the space physics community a unique opportunity to investigate the fundamental physical processes accompanying the solar wind (SW) interaction with the local interstellar medium (LISM).  The proposed session will address microscopic and macroscopic phenomena derived from IBEX and Voyager observations, and especially their combination. It will particularly focus on the following scientific questions:

  1. What is the effect of the coupling of the heliospheric and interstellar magnetic fields at the heliopause? What is the correlation between observations and model predictions for the magnetic field and plasma quantities? What do space-time variations in the magnetic structure tell us about the physics of the heliosphere and termination shock?
  2. What are the physical mechanisms of the IBEX ribbon and distributed ENA fluxes?
  3. What are the ion acceleration mechanisms in the inner heliosheath? How do anomalous cosmic rays affect the structure of the heliosphere? What are the reasons of the variation in the galactic and anomalous cosmic ray fluxes observed by Voyager 1?

Scene-setting presentations will be given by David McComas and John Richardson on behalf of the IBEX and Voyager mission teams, respectively, and followed by a discussion on the themes of the session.

TOP


14. The Topology of Coronal Magnetic Fields
Kalman Knizhnik (JHU/NASA GSFC) & Marc DeRosa (LMSAL)

Session Description

Magnetic reconnection sites associated with solar eruptions are often located in or near topological features of the coronal magnetic field. As a result, being able to map out the coronal field topology and determine which features are important would significantly contribute toward the ability to accurately forecast solar eruptions. However, because the structure of coronal magnetic fields cannot be measured directly, the observations must be complemented by numerical models in order to correctly identify and interpret the field topology. In this session, we will explore the following questions:

-- What topological features of active region magnetic fields play an important role in determining eruptive behavior?

-- How can coronal observational signatures be combined with modeling efforts to distinguish topological features of interest?

-- What advances in data products or modeling techniques are needed to improve the usefulness of topological mappings in understanding the evolution of the coronal field?

TOP


15. The magnetic nature of Solar Filaments
R.T.James McAteer (NMSU), Valentin Pillet (NSO)

Session Description

We propose a half-day SHINE session to discuss the magnetic nature of solar filaments, focusing on two overarching science questions.

  1. What is the magnetic field configuration of unstable solar filaments?

  2. How does the magnetic field in erupting filaments manifest in disturbances at 1AU?

Given the impact of filament eruptions throughout the heliosphere, the objective of this session is

to clarify where our understanding of filament magnetic structure and most importantly its destabilization, lies. We seek to engage experts in spectropolarimetry instrumentation, flux rope modeling, CME propagation observations, and Space Weather predictions in a discussion on solar filament magnetic fields. We seek to determine the future requirements in instrumentation and modeling that are necessary to replace ad-hoc (often missing) input of filament magnetic fields with near-realtime data. The interaction of the filament magnetic field (and that of the magnetic cloud) with the background solar wind plays a key role in predicting Bz at 1AU.

Solar filaments remain an enigma in the three important interconnected aspects of formation, structure, and stability. They form suddenly and quite spontaneously, sometimes in regions of preexisting magnetic flux and sometimes in regions of quiet Sun, but always over magnetic neutral lines. As they are cold dense chromospheric plasma surrounded by the hot, low density corona, their structure should both thermalize and collapse soon after formation. However they can be stable for several complete solar rotations. Conditions postulated to explain this stability, must simultaneously allow for the sudden and rapid removal of this stability as a large scale energy release in the form of a coronal mass ejection.

It is clear that magnetism plays a fundamental role in all three stages: it is the nature of magnetism to form linear, sheared structures that allows for their formation; the lack of cross- field drift in the structure shields the filament plasma from the rest of the corona; magnetism can suddenly rearrange its structure with a sudden loss of stability. However this magnetic field is currently only included as an ad-hoc input in our models (and is often ignored altogether). In this session we will address the key elements of what data we can currently input into models, how this could be implemented, and what future data may become available over the next few years.

 

TOP


16. Coronal Model Drivers: a fistful of maps
Carl Henney, Nick Arge, Jon Linker, Anthony Yeates

Session Description

Goal: To address the key challenges of generating global solar magnetic field maps and to understand how “poor” maps affect coronal and solar wind model results. For this initial “challenge event” study, a single date and time, 20 UT on July 8th 2010, has been selected to compare global magnetic maps (provided by “map makers”) and model output (provided by “modelers”) generated from the contributed maps. This session will be divided into 2 parts:

  • Map contributors outlining methods; plus general comparisons & metrics
  • Modelers provide comparison, feedback, & "fall out". Plus, where to go next.

Map contributors need to provide radial field maps (i.e., 360x180, fixed Carrington, in Longitude vs. Latitude, via FITS format) for the challenge event by June 3rd. Modelers need to provide maps of open field regions (i.e., coronal holes) derived from the models and comparisons between in-situ observations & solar wind forecasts, based on contributed maps by July 1st.
Background:  Global magnetic maps are made using numerous methods that range from extremely simplistic (e.g., assuming the sun rotates as a solid body) to attempting to model magnetic flux transport processes. Depending on the method and the complexity of activity on the sun, the maps can include a large monopole moment, poor or no data for a given pole, lack of flux evolution on the far-side, and poor field orientation assumptions when mapping from line-of-sight to the final global radial field map. All these artifacts have tremendous influence on heliospheric models. The session will have active discussion on the techniques for minimizing problems for the selected dates during the “challenge event” period.
Questions to be addressed:

  • What are the biggest challenges to estimating the structure of the global corona?
  • How best to estimate the far-side & poles?
  • How best to quantify (i.e., global & observational metrics) and validate success?

TOP


17. The impact of high-resolution solar observations on understanding in situ measurements in the inner heliosphere
Phyllis Whittlesey, Mike Stevens, Ed Deluca

Session Description

To solve the next generation of heliophysics science questions, data from as many sources as possible will be needed to make significant progress. In the era of Solar Probe Plus, Solar Orbiter, DKIST, IRIS and SDO, we will need to combine data in a useful way to address fundamental questions. In this session we will examine the use of remote sensing and in situ data to address coronal heating as well as solar wind acceleration. By reviewing the data currently available as well as what will be available from missions such as Solar Orbiter and Solar Probe Plus, we will discuss how to best incorporate both types of data to address the science questions. In addition, any we look at other complementary studies such as jets, coronal mass ejections, and flares.

Some questions for discussion are:
1.) How will imaging of the solar disk and sampling the plasma at 10s of solar radii aid in understanding solar wind origin, evolution and acceleration?
2.) Can spectroscopy on the solar disk aid in interpreting the composition measurements in the inner heliosphere?
3.) What tools are available currently to match in situ data to remote sensing data?
4.) What models/tools will have to be created to help answer these scientific questions?
5.) What signature of high resolution remote sensing data should we "see" in in situ data? Jets? Magnetic reconnection regions? Bi-directional electrons indicating magnetic connectivity?

TOP


18. Science from the Solar Eclipse 2017
Ed Deluca, Matt Penn, Shadia Habbal

Session Description

In August 2017, there will be the Great American Eclipse with the path of totality stretching across the continental United States from Washington to the Carolinas. In addition to the amazing public outreach planned though various organizations (Citizen CATE Experiment, Eclipse Megamovie etc) we are looking to discuss the scientific results that could be possible from this eclipse opportunity.

We would look to address some of the following topics:

1. Coronal science with 3.5min of data - Possibilities for Continuous Coverage in 2017?

2. Multi-spectral range observations: Opening the IR window - past and future coronal observations beyond 1 micron; polarization measurements; waves and flows

3. High resolution observations - coronal structure out to 3Rs; comparison with global coronal models

4. Multi-instrument observations - expectations from combined space based and ground based observations.

Questions to be addressed by this session:

1.) what science might be done by a sequence of observations along the eclipse path (a lot more time than 3.5 minutes)? What is already being planned? What could be planned?

2.) How will we synthesize the data from various sources to advance understanding of the corona?

3.) What do we expect to see using the eclipse versus our space based assets?

4.) What would the coronal structure in the IR tell us?

TOP


19. The Origin of Non-Eruptive Large Flares
Xudong Sun, Tibor Torok, & Nariaki Nitta

Session Description

Intense solar flares are often, but not always, associated with a coronal mass ejection (CME) that may impact the heliosphere. We know of several examples of large flares without CMEs and refer to them as non-eruptive. For example, TRACE data showed a nice filament eruption associated with an M-class flare (2002 May 27), but it did not reach coronagraphic heights and was thus called a failed eruption. More recently, none of the six X-class flares from AR 12192 (the largest active region since 1990) in October 2014 was accompanied by a CME. These events have triggered exciting investigations in data analysis, theoretical modeling, numerical simulations and laboratory experiments to identify the factors that determine the eruptiveness of a flare. However, the origin of non-eruptive flares is still not well understood.

In this session, we solicit discussions focusing on the conditions that determine whether a flare is eruptive or non-eruptive (defined here by its association with a CME). Questions of particular interest include:

-- What are those conditions and can we predict them based on photospheric magnetograms and other observations?

-- Are different initiation and energy dissipation mechanisms responsible for eruptive and non-eruptive flares?

-- How can we interpret results from theoretical, numerical and laboratory works in terms of observations?

TOP


Conference Links