# Preferential Heating and Acceleration of Heavy Ions in Impulsive Solar Flares

## TL;DR

This study uses 3D PIC simulations to demonstrate that in impulsive solar flares, heavy ions are preferentially heated and accelerated perpendicular to the magnetic field, aligning with observed non-thermal features.

## Contribution

It provides the first detailed simulation-based evidence that heavy ions are preferentially energized via cyclotron resonance in turbulent solar flare environments.

## Key findings

- Heavy ions gain energy faster than lighter ions.
- Ion heating is predominantly perpendicular to the magnetic field.
- Simulation results match analytical estimates of cyclotron resonance heating.

## Abstract

We simulate decaying turbulence in a homogeneous pair plasma using three dimensional electromagnetic particle-in-cell (PIC) method. A uniform background magnetic field permeates the plasma such that the magnetic pressure is three times larger than the thermal pressure and the turbulence is generated by counter-propagating shear Alfv\'en waves. The energy predominately cascades transverse to the background magnetic field, rendering the turbulence anisotropic at smaller scales. We simultaneously move several ion species of varying charge to mass ratios in our simulation and show that the particles of smaller charge to mass ratios are heated and accelerated to non-thermal energies at a faster rate, in accordance with the enhancement of heavy ions and non-thermal tail in their energy spectrum observed in the impulsive solar flares. We further show that the heavy ions are energized mostly in the direction perpendicular to the background magnetic field with a rate consistent with our analytical estimate of the rate of heating due to cyclotron resonance with the Alfv\'en waves of which a large fraction is due to obliquely propagating waves.