# Cross helicity sign reversals in the dissipative scales of magnetohydrodynamic turbulence

## TL;DR

This study uses direct numerical simulations to investigate how cross helicity sign reversals occur across different scales in MHD turbulence and their relation to magnetic reconnection regions.

## Contribution

It reveals the scale-dependent sign reversal of cross helicity and links it to magnetic reconnection activity in nonlinear MHD turbulence.

## Key findings

- Cross helicity changes sign from large to small scales.
- Magnetic reconnections are strongest where cross helicity sign reverses.
- Regions of minimal cross helicity are associated with intense reconnections.

## Abstract

We perform direct numerical simulations of magnetohydrodynamic (MHD) turbulence with kinetic energy and cross helicity injections at large scales. We observe that the cross helicity changes sign as we go from large and intermediate scales to small scales. In addition, the magnetic reconnections are strongest at the regions where the cross helicity changes sign and becomes smallest in magnitude. Thus, our simulations provide an important window to explore the regions of magnetic reconnections in nonlinear MHD.