WG1: Electron acceleration and transport
Leaders: Marina Battaglia, Frederic Effenberger
During a solar flare, electrons are accelerated and transported both towards the lower atmosphere as well as into interplanetary space. RHESSI’s hard X-ray and gamma-ray observations allow important insights into the acceleration and transport of these electrons, especially when combining them with observations made with other instruments at different wavelengths (i.e., soft X-ray, radio, and EUV), numerical simulations, and theory. This group focuses on recent advances in this field, and particularly encourages contributions from multi-wavelength observations and comparisons of models with RHESSI and MinXSS observations.
Leader: Albert Y. Shih
Ions from solar eruptive events are observed directly in solar energetic particle events and indirectly through secondary nuclear gamma-ray lines, pion-decay emission, neutrons, and even energetic neutral atoms. This group will discuss such observations, primarily gamma-ray data from RHESSI and Fermi, in the context of acceleration processes associated with flares and CME shocks. In particular, the Fermi/LAT observations of >~100 MeV emission, both impulsive and long-duration, require an improved description of how the most energetic particles are accelerated and transported. We will also discuss recent observations that relate to ion acceleration, such as neutrons in the inner heliosphere and at 1 AU and terahertz emission. Finally, we will discuss what new observations can be made in the coming years.
WG3: (Solar) Atmospheric response
Leaders: Juan Carlos Martínez Oliveros, Fatima Rubio da Costa
Perhaps the most dramatic processes in the Sun are solar flares, releasing vast amount of energy within short timescales and emitting in a wide spectrum of wavelengths. This energy is transported along the solar atmosphere and deposited at different layers. Determining the relation between thermal and non-thermal radiation with other wavelengths is a key study for the understanding how the particles interact with the lower solar atmosphere since the emission at each wavelength is associated with different physical processes. A zoo of phenomena accompanies these events and their analysis can provide a wealth of information about the solar atmosphere. This group focuses on the manifestation or response of the solar atmosphere to flares and other energetic events (e.g., CMEs), from the corona to the solar interior and how multi-wavelength observations (i.e., RHESSI, MinXSS, IRIS, SDO, Hinode, NuSTAR, NoRH, and OVSA) can help our understanding of the mechanics of momentum and energy transfer in the solar atmosphere. We invite both modeling- and observationally-driven contributions exploring the response of the solar atmosphere to flares and other energetic events.
Leaders: Laura Hayes, Bin Chen
Radio and X-ray observations have long proved useful in the diagnostics of energy release and properties of electron acceleration during solar flares. Flaring radio emission, in particular, is produced by a number of different physical mechanisms, and hence provides a wealthy diagnostic that complement HXR measurements. The era of RHESSI has granted significant progress in the understanding of the radio/HXR relationship, and has proved the value in utilizing radio and HXR data simultaneously in the study of energetic electrons, both thermal and nonthermal, in the corona.
We now enter a new stage of improved radio spectral imaging capabilities such a the first solar ALMA observations at mm wavelengths, along with exciting new science opportunities from other radio instruments such as EOVSA, EVLA, LOFAR, MUSER, LWA, and MWA. These, in conjunction with RHESSI and the future Solar Orbiter/STIX, will allow for new insights into the relationship between radio/HXR emissions.
This working group will focus on discussions of joint radio/HXR observations, and we encourage participation from both an observational and theoretical perspective. We aim to highlight the progress RHESSI has made in simultaneous radio and HXR observations, and we’ll discuss future prospects in the capabilities of these joint observations on our current understanding of solar flares.
WG5: RHESSI imaging: next steps
Leaders: Säm Krucker, Richard Schwartz
This working group will discuss the next steps in RHESSI imaging including topics such as harmonics, imaging at highest spatial resolution, pile up correction for imaging, high-time resolution imaging, difference imaging with visibilities, etc. It is planned to have short presentations of the current state of each topic, followed by discussions how to best tackle the remaining open issues. The goal is to have a prioritized list of tasks that we want to work on and follow up at the next RHESSI workshop.
Leaders: Jeffrey Reep, Natasha Jeffrey
15 years of RHESSI X-ray imaging and spectroscopy observations have improved our understanding of solar flares and the production, acceleration, and transport of high-energy particles, as well as the transport of energy through the solar atmosphere. Other instruments (e.g. MinXSS, IRIS, Hinode/EIS) complement our understanding of these processes, and provide insight in ways that any single instrument cannot do alone. Further, the next decade will look beyond RHESSI with new X-ray observations and diagnostics from the next generation of missions (e.g., MinXSS-2, Solar Orbiter/STIX, FOXSI) bringing a new set of challenges and questions, which will require the development of theory, models and diagnostic tools. This working group welcomes all contributions that aim to address these challenges, as well as weaknesses in our current understanding of the solar flare process.
Plenary Session: New Instrumentation
Leader: Lucia Kleint
This special plenary session, to be held on the final day of the workshop (Saturday, 24 June), will consist of a series of discussions related to the latest developments in observational technologies and their implementation as new missions or ground-based observations.