28 September 2020 to 2 October 2020
Pisa, Italy
Europe/Rome timezone

Group Summaries

Working Group 1

Leaders: Albert Y. Shih, Sam Krucker

Space-weather origins and the FIERCE mission concept

What triggers solar eruptions and the release of particles into the heliosphere is a long-standing debate.  Many models for the initiation of solar eruptive events involve magnetic reconnection, which results in both plasma heating and particle acceleration in the vicinity of the reconnected field lines, but the predicted timings and locations for the reconnection process – and the associated X-ray and EUV emissions – varies with model.  The energetic particles in the heliosphere can be measured in situ by missions such as Parker Solar Probe and Solar Orbiter, but understanding the physical origin of these particles requires remote observations of the transient phenomena (e.g., solar eruptive events, jets) that accelerated the particles.  The Fundamentals of Impulsive Energy Release in the Corona Explorer (FIERCE) mission concept – recently proposed to NASA – would make unprecedented X-ray and EUV observations to address the above science, as well as other open questions in solar physics.  This working group will discuss the theoretical predictions and observational signatures of the physical origins of space weather, and the anticipated science results enabled by FIERCE and other future observations.




Working Group 2

Leaders: Gregory Fleishman, Diana Morosan

Radio diagnostics for accelerated electrons

Traditionally, RHESSI workshops focused on various aspects of acceleration, transport, escape, and impact of solar accelerated nonthermal particles. A highly useful complementary window to look at these processes is also provided by radio observations. Recently, new radio instrumentation with increased imaging and spectroscopic capabilities came on-line, which is capable of significantly advancing solar physics. These radio observations provide plasma, magnetic field and particle diagnostics in the corona, complementing hard X-ray diagnostics in the chromosphere and dense coronal structures. This working group will focus on results from these new radio instruments, associated modeling/simulation studies, and theoretical developments, as well as multi-wavelength investigations including joint radio and X-ray studies. We welcome contributions that focus on the solar radio science, particularly, addressing solar eruptions, and highlighting the complimentary nature of radio and X-ray observations.


Working Group 3

Leaders: Alexandra Lysenko, Melissa Pesce-Rollins

Ion studies and Fermi/LAT

Over the past 12 years, Fermi-LAT observations of high-energy solar flares have revealed an extremely rich and diverse sample of events with a wide variety of characteristics providing valuable information on accelerated ions. In order to fully understand the acceleration mechanisms at work during these flares it is imperative to combine  gamma-ray observations with the observations of the UV/optical/IR/radio counterparts as well as the frequently accompanying CMEs and SEPs. Although there are space-based observatories in high energy range operating at present, every instrument has its own limitations, thus it is also important to understand what new observations are needed and to develop requirements for potential future instrumental capabilities. This working group invites contributions relating to solar flares observed in gamma-ray range by Fermi-LAT and other instruments and their connection with multiwavelength counterparts, theory/modeling of the acceleration processes associated with these flares. Also contributions on new instrumentation requirements in gamma-ray range are welcomed.


Working Group 4

Leaders: Silvina Guidoni, Joel Dahlin

Energy release and particle acceleration

Description coming soon



Working Group 5

Leaders: Jeff Reep, Laura Hayes

Atmospheric Response

Understanding the deposition and transport of energy across the solar atmosphere is a critical problem in solar physics.  In flares, the time scale for energy release is short, so that the plasma evolves rapidly, necessitating high cadence observations and modeling to understand the dynamics.  Furthermore, the energy transport occurs across the entirety of the atmosphere – from the corona through the deep chromosphere and perhaps to the photosphere.  The observational coverage of X-rays, EUV, and radio waves have all shed light on the non-thermal and thermodynamic processes occurring in flares, as well as allowing for model tests and validation.  In this session, we will address the thermal response of solar flares to the impulsive energy release that drives them.  We invite contributions that discuss the modeling, observations, and the inter-comparison between the two that can improve our understanding of flares.  We encourage discussions of potential capabilities of Solar Orbiter or DKIST, additionally.


Working Group 6

Leaders: Juan Carlos Martinez Oliveros


RHESSI provided over 16 years of groundbreaking measurements to revolutionize the field of high-energy solar physics. New soft and hard X-ray and gamma-ray instrumentation has been and is being developed, notably on the FOXSI rockets and pending SMEX, the PhoENiX mission concept, the MinXSS CubeSats, CubIXSS, MiSolFA and MiXI mission concepts, the MaGIXS rocket, the GRIPS balloon, and others that will continue and expand upon RHESSI’s outstanding legacy. This session invites presentations on additional new technologies, instruments, and orbital,  or sub-orbital and ground-based concepts that can provide new and deeper insights into high-energy processes in the solar corona. This is not limited to X-ray/gamma-ray observations, but includes radio, UV/EUV, energetic particles, and other measurements that can shed light on solar eruptive processes and high-energy coronal physics, particularly in combination with upcoming and/or proposed X-ray missions such as FOXSI SMEX, Solar Orbiter / STIX, PhoENiX, and others.