Time adaptive PIROCK method with error control for Multi-Fluid MHD systems: Application to the reconnection problem in the solar atmosphere simulation (Q.M. Wargnier, Lockheed Martin Solar and Astrophysics Laboratory and Baeri)

16.05.2023 14:00

The extent of our knowledge on magnetic reconnection (MR) in chromospheric conditions is currently restricted. Studies have indicated the significant contribution of ion-neutral interactions to the behavior of the chromosphere. Additionally, the dissimilarity between the spectral profiles and simulated observations of reconnection implies that single-fluid magnetohydronamic (MHD) models do not align with empirical evidence. This inconsistency can be attributed to various factors such as collisions, multi-thermal properties of plasma, and the effects of hydrogen and helium ionization, all of which have a considerable impact on the energy equilibrium of the chromosphere.

In this study, we explore the influence of multi-fluid/multi-species (MFMS) effects on MR in the upper chromosphere. Our investigation involves a comparison between an MFMS model that employs a mixture of helium and hydrogen, and a two-fluid MHD model that solely employs hydrogen. We examine the progression of MR in both models while considering various factors such as the separation of particles, the alteration of heating mechanisms, and the changes in composition.

The simulations were conducted using the Ebysus numerical code (Wargnier et al. 2023), which is capable of resolving any MFMS model with customizable species and ionized/excited levels. The numerical strategy employed in this study involves an implicit-explicit partitioned orthogonal Runge-Kutta method developed by Abdulle & Vilmart (2013). This approach optimizes the timestep and also estimates the error associated with the various components of the MFMS models while keeping computational expenses within reasonable limits.

This is work with:
Q.M. Wargnier (1,2), G. Vilmart (3), J. Martinez-Sykora (1,2,4) , V. H. Hansteen (1,2,4,5), and B. De Pontieu (1,4,5)
(1) Lockheed Martin Solar and Astrophysics Laboratory, USA
(2) Bay Area Environmental Research Institute, USA
(3) Section of Mathematics, University of Geneva, Switzerland
(4) Rosseland Centre for Solar Physics, University of Oslo, Norway
(5) Institute of Theoretical Astrophysics, University of Oslo, Norway

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