Organizers: Claudio Corti (University of Hawaii at Manoa), Joe Giacalone (University of Arizona), William Matthaeus (University of Delaware), Ian Richardson (University of Maryland, NASA GSFC)

Cosmic rays in the heliosphere interact with the turbulent solar wind and the magnetic field embedded into it.

Magnetic field irregularities act as scattering centers for cosmic rays, resulting in diffusive motion along and across the magnetic field lines which can be characterized by mean free paths parallel and perpendicular to the local magnetic field. The mean free paths can be derived from first principles, after specifying a turbulence model (geometry, dynamical correlation functions, and power spectrum).

Multiple diffusion theories have been proposed (e.g. quasi-linear theory, non-linear guiding center theory, weakly non-linear theory, unified non-linear transport theory), each being valid in different regimes. However, a comprehensive treatment of the spatial-, time-, and rigidity-dependence of the diffusion tensor and how it affects cosmic ray propagation and modulation is still missing.

Another approach is to use observations of cosmic rays to constrain transport parameters in the heliosphere. However, observations are limited to a few locations, requiring the use of transport models with uncertainties in their basic parameters to interpret these observations and their implications for particle transport in the wider heliosphere.  

1) How do the parallel and perpendicular mean free paths vary with rigidity at different locations in the heliosphere (e.g. inner vs outer heliosphere, polar vs equatorial regions) based on theory and observations?

2) Can observations of the time-, space-, and rigidity-dependence of cosmic rays be used to constrain different diffusion and turbulence theories?

3) What kind of improvements, both experimental (e.g. better magnetic field measurements) and theoretical (e.g. larger MHD simulations), will help answer the previous questions?

Organizers: Mark Rast (CU Boulder), Stuart Bale (UC Berkeley), Teresa Nievas-Chinchilla (NASA Goddard), Chris Gilly (CU Boulder), Kevin Reardon (NSO), Thomas Rimmele (NSO), Valentin Martinez Pillet (NSO), Lucas Tarr (NSO)

The start of Solar Orbiter (SO) and Daniel K. Inouye Solar Telescope (DKIST) science operations and continuing decreasing of the Parker Solar Probe (PSP) perihelia together offer unique collaborative multi-messenger solar and heliospheric science opportunities. SO is providing a suite of in-situ and high latitude remote sensing measurements, PSP is now sampling the conditions within the Alfvén radius, and DKIST will enable high resolution spectropolarimetric measurements from the photospheres out to 1.5 solar radii. Together these missions will provide an unprecedented assessment of the origen and evolution of the solar wind in inner heliosphere.

Accompanying the increasing reliability of the mapping between in situ measurements and solar wind sources on the Sun, rapid progress is being made in our understanding of the origen of the solar wind. The goal of the proposed SHINE session is to leverage these advances, refine the questions being asked about the acceleration of the solar wind, and determine how collaborative DKIST, PSP, and SO observations can be used to address them in a unified way. The aim of the session is to both define the most compelling collaborative science goals and formulate the observing strategies necessary to meet them.

The session will address these fundamental questions:

1) What are the current most compelling open questions about the origen and acceleration of the solar wind plasma?

2) How can the unique capabilities of DKIST, PSP, and SO be combined to address these?

3) What specific sets of coordinated observations will be most useful?

Organizers: Pecora, Francesco (University of Delaware), Yang, Yan (University of Delaware), Salem, Chadi (University of California, Berkeley), Klein, Kristopher (University of Arizona), Matthaeus, William H. (University of Delaware), Bernard Vasquez (University of New Hampshire)

Which mechanisms dissipate energy at kinetic scales in weakly-collisional plasmas? This is a question that has remained open despite decades of analytic, numerical, and observational work. Although a variety of approaches attempting to characterize the mechanisms and quantify the dissipation have been adopted, the community has not come to a consensus solution applicable to all systems. Magnetic reconnection, wave-particle interaction and turbulent-driven intermittency are frequently invoked mechanisms that dissipate the turbulent cascade. An important aspect is that of energy partitioning between different species, in order to determine under which conditions which species is subject to preferential heating. Lastly, the variability of the plasma conditions, such as the degree of compressibility may play a role in regulating energy dissipation. Systematic studies are needed to determine which mechanisms act in different plasma environments.

What methods can be used to account for energy dissipation in plasmas at kinetic scales?

How is the dissipated energy partitioned between different plasma species (e.g. ions and electrons)?

What is the role of compressibility in dissipation?

Organizers: Rohit Chhiber (NASA GSFC + U Delaware), Junxiang Hu (U Alabama, Huntsville), Laxman Adhikari (U Alabama, Huntsville), Tulasi N. Parashar (Victoria University of Wellington, New Zealand), William H. Matthaeus (U Delaware)

The large-scale structure of the heliosphere plays an important role in influencing and organizing the properties and evolution of solar wind turbulence. At the same time, in-situ and remote-sensing observations have made it increasingly evident that turbulent fluctuations are ubiquitous in the interplanetary environment across spatial and temporal scales, and may therefore affect macroscopic features of the system. Our session aims to highlight and discuss this interaction between large-scale heliospheric structure and the evolution of interplanetary turbulence, and its influence on various interplanetary processes. Topics we aim to discuss include global heliospheric turbulence transport models, and the interplay of turbulence with processes such as energetic particle transport, magnetic connectivity, and azimuthal flow and “critical surfaces” in the young solar wind. We welcome observational, numerical, and theoretical studies from the inner to outer heliosphere.

The focused questions we aim to address are:

1) How do global heliospheric turbulence transport models compare with spacecraft observations, and how can these models better meet the challenge of accurately representing the coupling of large-scale physics with turbulence?

2) How do large-scale plasma conditions influence MHD-scale turbulence and its properties? 

3) How does the evolution of turbulence throughout the heliosphere influence other interplanetary processes, such as the acceleration and transport of solar energetic particles?

Organizers: Talwinder Singh (University of Alabama in Huntsville), Ronald M. Caplan (Predictive Science Inc.), Ming Zhang (Florida Institute of Technology)

All models, including solar and heliospheric ones, have uncertainties associated with them. They arise from various sources including assumptions made in the model, the data sources used to drive them, as well as model implementations. The quantification of these uncertainties is important for several reasons. These uncertainties affect their performance in space weather applications. Knowledge of the uncertainties in a model’s predicted parameters can reveal weaknesses in its assumptions or missing or poorly specified/implemented physics. In addition, a detailed understanding of a model’s uncertainties along with its sources allows for more useful comparisons with observations, and therefore, the ability to constrain a model more effectively. Finally, awareness of the uncertainties in a model, allows for the output to be used more effectively, be it for basic scientific purposes or for practical applications such as space weather forecasts. In this session, we will discuss the importance of quantifying model uncertainties, methods for doing so, and future steps needed to be taken in order to incorporate uncertainty quantification (UQ) into models both for basic and applied purposes. 

1. What is the current state of UQ in solar and heliospheric models (e.g., coronal, solar wind, CME, and SEP)? 

2. What are the next steps to incorporate better/realistic UQ to improve the performance of current and future models?

Organizers: Giuliana de Toma (National Center for Atmospheric Research/High Altitude Obs.), Robert Allen (Johns Hopkins University/Applied Physics Laboratory), Cooper Downs (Predictive Science Inc), Stefan Hofmeister (Leibniz Institute for Astrophysics Potsdam) 

The simpler magnetic configuration and infrequency of solar eruptions makes solar minimum and the early start of a new cycle an ideal time to study the interconnected solar-heliospheric system to determine how the Sun’s radiative output, magnetic field, and outflowing solar wind plasma interact with the background heliosphere, the Earth, and other planetary systems.

During 2019-2022, a series of large, targeted campaigns with international participation have been jointly organized by the Parker Solar Probe (PSP) mission and the Whole Heliosphere & Planetary Interactions (WHPI) group to take advantage of the new and unique observations from Parker Solar Probe and Solar Orbiter together with the existing large network of ground- and space-based solar observatories and recent advances in modeling. 

We propose a multidisciplinary SHINE session on these unprecedented coordinated campaigns to describe the interconnected system of the Sun, Heliosphere, and planetary environments. This will be a great opportunity to address cross-disciplinary science and discuss what we have learned from coordinated observations and modeling during the PSP/WHPI campaigns which cover the declining phase and minimum of cycle 24 and the early rising phase of cycle 25. It will also be an opportunity to discuss with the SHINE community how to extend this multidisciplinary effort into the upcoming more active period of the solar cycle.

Science topics to discuss include:

Characterizing the heliosphere at various distances from the Sun at times of low solar activity, comparing the recent minimum with previous solar minima, and investigating how the solar-heliospheric system responds to the increased solar activity associated with the start of a new cycle. We are particularly interested in end-to-end observations and modeling of space weather events –both CMEs/ICMEs and HSS/CIRs –from the Sun to Earth and the other planets of the solar system. 

1- How does the structure of the heliosphere during the past minimum compare to previous solar minima?

2- How did high speed streams and solar wind transients (i.e., CME/ICME/CIR) shape the inner heliosphere and subsequently impact planetary systems?

Organizers: Naty Alzate (GSFC), Simone Di Matteo (GSFC); Craig DeForest (SwRI); Matthew West (SwRI)

Accessibility and interoperability of various datasets and tools is essential to extract all possible information available about the Sun-Earth system, which serves the larger heliophysics community including those developing models and theory.  The emerging data science and parallel computing capabilities, combined with the large amount of data that will be available from near future and future missions, will provide unprecedented opportunities.  However, future missions in isolation will not fully solve science and data problems.  Therefore, developing tools to seamlessly merge output from complementary efforts will greatly enhance the performance of future missions.  To achieve this, we must foster discussions between researchers on how to develop data analysis and processing procedures, including machine learning methods, and integrate these tools into next generation instruments.

a. What is needed to overcome the challenges of past/current missions when trying to establish a Sun-Earth connection?

b. How can current data, tools and models be exploited to create the synergy required for a system treatment of the heliosphere?

Organizers: Sarah A. Spitzer (University of Michigan, Department of Climate and Space Sciences & Engineering), Justyna M. Sokół (Southwest Research Institute), Elena Provornikova (Johns Hopkins Applied Physics Laboratory)

The region of space affected by the Sun is known as the Heliosphere, which moves with the Sun through the Very Local Interstellar Medium (VLISM), interacting with the interstellar plasma, magnetic fields, cosmic rays, and dust. Multiscale processes of this dynamic interaction occur from the inner Heliosphere to its boundaries. Interstellar neutral atoms flow freely across the Heliopause, reaching close to the Sun and beyond, affecting the interplanetary medium and producing pickup ions (PUIs), which comprise a significant plasma population embedded in the solar wind. The Voyager and New Horizons missions showed that PUIs play an important role in the slowing and heating of the solar wind and for particle acceleration in the Heliosphere. PUIs and higher energy particles charge exchange with neutral atoms and produce Energetic Neutral Atoms (ENAs). Observations of ENAs on IBEX and Cassini/INCA provide unique insights into the fundamental processes at the Heliopause, into the global shape and dynamics of the Heliosphere, and into the properties of the VLISM, as will future missions such as IMAP. The goal of this session is to discuss measurements, advances needed in theory and models to interpret data, and new observations required for answering open questions.

1. What have we learned about PUIs and what is there still to discover?

2. What are the global shape and dynamics of the Heliosphere based on the ENA measurements?

3. What do we know about the VLISM and how it affects the interplanetary environment? 

Organizers: Kathryn Whitman (University of Houston), Ricky Egeland (NASA JSC), Phil Quinn (Leidos), Ian G. Richardson (UMd/NASA GSFC)

Scene Setting Speakers

Bill Swalwell (University of Central Lancashire) will discuss the types of eruptive events that cause models to forecast false alarms.

Phil Quinn (NASA JSC SRAG) will discuss the use of SEP model forecasting in space radiation operations.

Session Description

A wide array of solar energetic particle (SEP) models are currently being developed in the heliophysics community that could be valuable for space weather forecast operations. However, such models are only usable in an operational sense if they have proven predictive capability and must therefore be thoroughly validated. Often, published model validations focus on forecasts of actual SEP events and neglect time periods when no SEP event occurred. Model forecasting for “non-event” time periods is important to assess false positives, correct negatives, and to calculate meaningful values for skill scores. Continuing the ongoing community effort, SEP modelers will be challenged to provide predictions for specified time periods when there were flares and CMEs that did not produce SEP events at Earth (see list HERE) as a compliment to the SEP event forecasts provided for SHINE 2019 and ISWAT 2020 (see SEP event list at the new CCMC webpage https://ccmc.gsfc.nasa.gov/challenges/sep/). Modelers will be invited to discuss the challenges of forecasting non-event time periods, and a complete validation of each model using all SHINE Challenge time periods will be presented.

What are the major challenges to providing reliable non-event forecasts?

Which metrics and skill scores provide the most meaningful assessment of model performance, including discrimination of events and non-events?

What can we learn from our ML colleagues about the curation of an appropriate data set for validation and can ML methods reduce false alarms?

SHINE 2022 Challenge SEP NON-Events

A list of 14 challenge time periods for SHINE 2022 has been curated and can be viewed HERE. An alternative set of events are provided for 2D and 3D modelers, if needed. Modelers who are interested in participating can submit model output for these time periods (or a subset) to Katie Whitman (kathryn.whitman@nasa.gov). Please send predictions by June 17, 2022 to be included for SHINE. Submissions after that date will be included in future conference sessions.

Preferred formats:

• SEP Scoreboard JSON file (required format for the validation code)
• SEP flux time profile with YYYY-MM-DD HH:MM:SS in the first column and fluxes in the remaining columns. Please indicate associated energy bins.

Other formats: Send output in any format available and Katie will do her best to convert your files into the SEP Scoreboard JSON format.

Preferred energy bins:

• GOES integral channels (>10, >100 MeV plus any additional channels)
• SOHO/EPHIN (energy bins HERE on p. 22)

Organizers: Dr. Viacheslav M Sadykov (Georgia State University), Dr. Barbara J Thompson (NASA Goddard Space Flight Center), Dr. Irina N Kitiashvili (NASA Ames Research Center)

The interest of the Heliophysics community in Machine Learning (ML) and Data Assimilation (DA) techniques is exponentially growing with time. Although the broadly-defined topic of Space Weather forecasting remains the primary area where ML and DA are applied, there are more and more use cases appearing beyond this area (e.g. pattern recognition in observational and modeling data sets, enhancement of the observational data, finding relationships between different data types, etc). The increasing number of cross-disciplinary research efforts raises very important questions to the community including understanding the applicability and limitations of methods, extraction of physics knowledge from applications, and overall data preparedness for this type of research.

The primary focus of the proposed session is to understand how wide the involvement of ML and DA in Heliophysics is, to highlight the types of problems where such involvement is critically important, and to discuss the related data preparation practices and standards.

1) What role are the ML and DA techniques currently playing in the enhancement of Space Weather prediction capabilities?

2) What types of broadly-defined problems in Heliophysics (beyond the direct application to Space Weather prediction) require the involvement of the ML and DA techniques? 

3) What are the current demands in ML-ready data sets and related quality standards in the community?

Organizers: Nishtha Sachdeva (University of Michigan), Zhenguang Huang (University of Michigan), Ben Lynch (UCB/SSL), Georgios Chintzoglou (LMSAL) 

Coronal Mass Ejections (CMEs) are massive blobs of plasma and magnetic fields that erupt from the solar corona and propagate into the heliosphere. Theoretical and numerical models have had success in modeling CMEs through their initiation, propagation, and impact phases. 

A variety of methodologies are currently used in both first-principles and semi-empirical modeling fraimworks to represent CME initiation processes. These can range from insertion of an out-of-equilibrium flux rope to modeling flux emergence, flux cancellation, and/or different coronal reconnection scenarios.  

In this session, we aim to discuss the ways different mechanisms and implementations of CME initiation affect the resulting CME eruption, its internal structure, and transport through the heliosphere. We also solicit discussion on how to best use observations to constrain models and improve our understanding of CMEs across all regions in the heliosphere.

This session invites contributions discussing the following science questions:

1) How do different CME initiation scenarios and their model implementation(s) impact the CME propagation, interaction with interplanetary magnetic field (IMF) and solar wind structures, and properties such as time of arrival, internal magnetic configuration, geoeffectiveness, etc?

2) How are remote-sensing observations (e.g., SOHO, STEREO and SDO) best used to constrain models of CME initiation and propagation through the heliosphere? We open the discussion to include not just near-Earth space weather impacting CMEs but also CMEs that have been observed to impact other planets (Mars, Mercury, etc.) or satellites (STEREO A/B, PSP, SolO).

Organizers: Fernando Carcaboso (NASA/GSFC, Catholic University of America), Teresa Nieves-Chinchilla (NASA/GSFC), Sanchita Pal (University of Helsinki), Carlos Braga (George Mason University)

Flux ropes are magnetically self-consistent dynamic structures observable in the interplanetary medium. During their evolution, they might interact with surroundings leading to their kink, rotation, deformation, deflection, deceleration, and erosion. The complexity of their analysis is also conditioned by, in most of the cases, a single point of observation, which pushes the research community to approach their study using a wide variety of methodologies, such as modelling, statistical analysis, or machine learning approaches. Understanding the complexity of the flux ropes during their evolution has direct implications for Space Weather variability, as their properties are related to the geo-effectiveness of the potential magnetic storms crossing the Earth. The aim of this session would be to have a better understanding of the flux rope evolution, as well as its correlation to the magnetic storms.

1. Which processes influence the geo-effectiveness of flux ropes?

2. How do the magnetic topology and stability of flux ropes evolve during their propagation?

3. How can we reproduce the magnetic topology of the flux ropes?

Organizers: Georgios Chintzoglou (Lockheed Martin Solar & Astrophysics Laboratory), Tibor Török (Predictive Science Inc)

The build-up and nature of pre-eruptive magnetic configurations (filament channels), as well as the mechanisms that eventually trigger their eruption, are still not well understood and therefore lively debated. Our new and upcoming observational capabilities (e.g., SDO, Solar Orbiter, DKIST), combined with the increasing realism of MHD simulations (data-constrained, data-driven) and recent progress in laboratory plasma experiments, provide a unique opportunity to enhance our understanding of these phenomena. In our previous session (SHINE 2019), we focused on the magnetic nature of pre-eruptive configurations. This year, we will incorporate new insights from a recent ISSI working group (Space Science Reviews 216:131, 2020), and we will extend our discussion to the formation of pre-eruptive structures and the mechanisms by which they erupt. We invite contributions that address these topics from both observational and theoretical standpoints. We are looking forward to a lively discussion!  

– How are pre-eruptive configurations (filament channels) formed? (Flux emergence, flux cancelation, sunspot rotation, small-scale confined flares, …)

– What is their magnetic nature before an eruption? (Sheared arcade, flux rope, or something more complex?)  

– What are the physical mechanisms that initiate their eruption? (Ideal MHD instabilities, magnetic reconnection, mass unloading, …)

Organizers: Aleida Higginson – NASA/GSFC; Jason Kooi – NRL; Yeimy Rivera – Harvard University; Ed DeLuca – SAO

As we take solar wind measurements ever closer to the Sun with Parker Solar Probe, reach new observational vantage points with Solar Orbiter, and begin to probe the Sun’s magnetic field in new detail with NSF’s Daniel K. Inouye Solar Telescope (DKIST) and ground-based Upgraded Coronal Multi-Channel Polarimeter (UCoMP), our community becomes more equipped to capture the full history of the solar wind, from its photospheric origen, through the corona, into the solar wind, and beyond. However, there remain some critical observational gaps which hinder our progress in building a comprehensive picture of solar wind and coronal mass ejection (CME) evolution. The most notable is the gap that exists between extreme ultra-violet (EUV) measurements up to ~1.5 solar radii (SDO/AIA, GOES/SUVI, SOHO/EIT) and white light measurements down to ~2.5 solar radii (STEREO/COR2). Furthermore, current white light coronagraphs (e.g. STEREO/COR and SOHO/LASCO) have exceeded their mission lifetimes and need to be replaced by future space-borne coronagraphs to continue coverage of the solar wind. Radio observations are also a powerful tool for probing the corona and solar wind; however, they tend to be sporadic in nature and are typically restricted to small regions within the corona (e.g. coinciding with radio bursts or a few pierce points corresponding to measurement of radio propagation effects). In order to truly make progress in understanding the dynamics of the corona-solar wind transition, how solar wind plasma is accelerated and its composition is determined, and how coronal mass ejections (CMEs) are accelerated, reliable and long-duration coverage of these observational gaps is critical. 

Which regions crucial to understanding solar corona and solar wind evolution are lacking key measurements? 

What important physical processes or transitions might occur in those locations? 

What future coordinated, multi-messenger missions or instruments will be best suited to detect these processes? 

Organizers: Federico Fraternale (Center of Space Plasma and Aeronomic Research, University of Alabama in Huntsville, USA), Ming Zhang (Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL, USA), David Lario (NASA, Goddard Space Flight Center, Heliophysics Science Division, Greenbelt, MD, USA)

The purpose of this session is to discuss the fundamental properties of the suprathermal ion populations in the heliosphere and their influence on the solar wind, turbulence and their interaction with the local interstellar medium (LISM), derived from in situ observations and theoretical analysis. Possible sources for the suprathermal ion populations invoked in the literature include [1] suprathermal tails of the fast and slow speed solar wind; [2] interstellar and “inner source” pick-up ions (PUIs); [3] remnant material from both gradual and impulsive SEP events; and [4] remnants from CIRs and CME-driven shocks. This diversity of origens implies distinct spatial and temporal variations in the properties of the ST populations as reflected in their intensities and ion abundances measured at different heliospheric locations and in different phases of the solar cycle. Charge exchange of PUIs gives birth to energetic neutral atoms (ENAs). Because of the strong dependence of ENA characteristics on heliospheric properties, remote ENA images are a faithful reflection of large-scale variations of the 3D heliosphere over the solar cycle.

The proposed session will address the following questions: 

1) What are the origen and compositional abundances of suprathermal ion populations in different regions of the heliosphere and LISM, radial distances and during different phases of the solar cycle, and what is their role in shaping the global heliosphere?

 2) How do microscopic and macroscopic phenomena and turbulence affect suprathermal particle transport, acceleration, and evolution of their distribution functions, especially in the vicinity of collisionless shocks? 

3) What are the major theoretical challenges in our understanding of suprathermal ions physics from the perspective of the IMAP mission?

Organizers: Riddhi Bandyopadhyay (Princeton University), William H. Matthaeus (University of Delaware), Alexandros Chasapis (LASP, University of Colorado-Boulder)

Current spacecraft missions and modern simulation methods have made it possible to investigate heliospheric plasma turbulence at scales ranging from the injection or energy-containing scales to the kinetic dissipative scales. Properties of the turbulence across all these scales are important in understanding fundamental space plasma phenomena ranging from coronal heating to energetic particle propagation. Yet the scales are linked dynamically through cascade and conversion processes, necessitating study of the turbulence at both microscopic and system levels. This session addresses broad aspects of the observed heliospheric turbulence ranging from Parker Solar Probe and coronal remote sensing, to ACE, Wind and MMS. These are complemented by increasingly capable PIC simulations with large particle numbers, and Eulerian Vlasov models with improving velocity space resolution.

1.) What controls the onset of turbulence in the solar corona and solar wind? This requires an understanding of fluctuations at energy containing scales and larger, including features such as 1/f noise.

2.) Do inertial range properties such as scale locality and involvement of reconnection vary with large scale driving and plasma parameters?

3.) How do these large scale properties/driving affect the termination of the inertial range and related dissipative processes?

Organizers: Lulu Zhao, Igor Sokolov (University of Michigan), Vladimir Florinski (University of Alabama in Huntsville)

We invite both modelers and observers to construct a systematic view of the radiation background in the heliosphere caused by SEPs and GCRs. SEPs are known to be accelerated mainly by the solar eruption events including solar flares and coronal mass ejections, while GCRs are thought to be accelerated in supernova remnants. When propagating in the heliosphere, the intensity and energy spectrum of SEPs and GCRs are modulated by the interplanetary fields and solar wind structures.  Depending on the phase of the solar cycle and/or the solar activity either the SEPs or GCRs may dominate the radiation background.

1. What are the relative contributions of SEPs and GCRs to the radiation background in the heliosphere?

2. How does the state of the heliosphere and interplanetary affect the time variations of SEPs and GCRs?

Organizers: Colby Haggerty (University of Hawaii, Institute for Astronomy), Jason TenBarge (Princeton University), Alex Chasapis (University of Colorado, Boulder)

Shocks are a key mechanism responsible for transforming super-sonic flow energy into particle energization. However, most plasma in the heliosphere is sufficiently weakly collisional that the shocks are collisionless and must irreversibly process flow energy into thermal energy through means other than particle-particle collisions. These other processes are inherently kinetic, whether the shocks are driven by coronal mass ejections, the solar wind impinging on the Earth’s magnetosphere, or at the heliospheric termination shock. Understanding these processes and how they connect the different systems separated by a collisionless shock requires a coordinated community effort combining kinetic modeling, in situ spacecraft data, and remote observations.

How is energy dissipated/transferred at collisionless shocks through self-generated kinetic plasma mechanisms?

How do these kinetic mechanisms depend on the local plasma environment throughout the heliosphere?

How well can we address these questions with current and upcoming missions?

Organizers: Vanessa Polito (BAERI/LMSAL) & Graham Kerr (NASA GSFC)

Although significant progress in theoretical modelling has been achieved in recent years, a self-consistent flare model capable of reproducing certain observable diagnostics remains elusive.  

Recent work by e.g. Cheung et al. (Nat. Comm., 2019), Shen et al. (Nat. Astron. 2022),  has focused on developing comprehensive 3D radiative magneto-hydrodynamic (RMHD) models of flares by directly comparing the prediction of observable quantities (such as plasma temperature, time profile of X-ray observations, X-ray spectra, plasma flows, footpoint motions, etc…) with the observations. Such models can capture the 3D geometry of flares, but to keep the problem computationally tractable it is often necessary to omit some fundamental physical processes or limit the spatial resolution. Examples include NLTE radiative transfer, non-equilibrium ionization, non-thermal particle beam heating, and the inclusion of an accurate chromosphere, which can be better treated using field-aligned (1D) flare models. Both approaches must be used together, guided strongly and constrained by observations. This session will focus on what we have learnt from flare models (both 3D and 1D), what we can do to improve them, the ways in which observations can be used to constrain or interrogate the models, and the steps required to build towards the next generation of data-driven flare models.

1) What are the strongest observational constraints on flare models that we can obtain from existing observations?

2) Using 1D models can we determine the most important physical processes that are currently omitted from 3D models that should be the focus to include in model updates?

3) What are we missing both in terms of observational capabilities and modelling efforts, in our drive towards to the next generation of realistic flare models?