Summary

Modelling the solar corona is essential to understand how it evolves. Over the last 20 years, we have built up a scientific community that are now worldwide expert in modelling the dynamics of the solar corona. To do so, we have been using the state-of-the art MHD code ARMS (developed by C. R. DeVore) that allows us to investigate various fundamental questions. The main science objective of our team is 1- to understand how the solar eruptive events (solar jets or CMEs) are triggered in the corona and how do they evolves 2 - How the solar corona dynamics contribute as a source of the solar wind. Our community is developing theoretical /numerical models addressing these questions and synthetic observable that can be compared to the observations as well. We selected the workshop format to allow discussions after the scientific talk and to organise technical session to learn from each other on the diverse options that can be implemented in the code. We expect to have fruitful discussion that will lead to efficient collaboration as it has been the case thanks to our every-6 month meeting starting in 2021. The first ARMS users meeting was organised at Paris Observatory in 2023 and sponsored by the Jules Janssen Center. The second in 2024 was organised in Boulder (USA). We will organise the third one in Paris again in 2025

Scientific justification

The main objective of the workshop is to gather the ARMS community during a face-to-face meeting to exchange on our scientific topics, create new collaborations between us, learn more about the options (physical and technical) available in ARMS and define what new physics we want to include in the code to develop more and more realistic models. The ARMS is the state-of-the-art code to study the solar corona. Thanks to its AMR and its numerical scheme it allows us to study accurately the dynamics of the corona by minimising artificial diffusion. One objective of the meeting is to exchange our skills in modelling the solar corona and learn how to maintain and develop the code in the future.
The ARMS users meeting allowed us to develop and maintain collaboration (see publication list), to produce a documentation of the code using the expertise of each of us, and to define new project and options that should be implemented in the code.

Preliminary program

The workshop will be split in two type of sessions. We plan to have scientific talks and technical talks on the numerical code and post-processing program developed by the community to share what we have been doing.
Concerning the scientific talk, every participants is asked to give a 20-30 minutes talk followed by 10 -15 minutes of questions.
The topics will focus on :
– modeling solar eruptive events
– modeling interchange reconnection as a source of the slow solar wind and solar jets
– understanding the solar source of switchback
– interpreting some of Parker Solar Probe and Solar Orbiter in-situ and remote observations
The numerical sessions will focus on 3 topic :
– boundary conditions,
– initialisation (B field, atmosphere and numerics :such as AMR criteria), – Synthetic observables : remote and in-situ