MMS observations of explosive filamentary current within two adjacent ion scale flux ropes

Flux ropes have attracted extensive attention due to their importance in studying instantaneous magnetic reconnection over the past years. Recently, with the improvement of high spatio-temporal resolution measurements, kinetic-scale flux ropes have been detected. However, their generation and energy energization are still unclear. In this study, electron-scale filamentary currents within two adjacent ion scale flux ropes are observed using MMS data. We find that:

1. Intense and explosive filamentary currents in parallel and perpendicular directions are found inside the flux ropes.

2. The electron pitch angle distribution appears "X" like shape, and could be caused by the electron acceleration.

3. The filamentary current appears in the center of the "X" distribution.

The filamentary currents are important and are considered to be the evidence of secondary reconnection [Wang et al., 2020]. The observations in our study are important to reveal the particle acceleration and energy dissipation in magnetic reconnection.