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Nonlinear evolution of the lower-hybrid drift instability in a current sheet
William Daughton1, Giovanni Lapenta, Paolo Ricci
1Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Physical Review Letters
|September 28, 2004
Summary
The lower-hybrid drift instability simulation shows that electron heating and current bifurcation accelerate magnetic reconnection in ion-scale current sheets. This finding is crucial for understanding plasma dynamics and space weather events.
Area of Science:
- Plasma physics
- Space physics
- Astrophysics
Background:
- Ion-scale current sheets are critical regions in space plasmas.
- Understanding instabilities in these regions is key to phenomena like magnetic reconnection.
- Previous simulations often used fluid approximations or limited kinetic regimes.
Purpose of the Study:
- To investigate the nonlinear development of the lower-hybrid drift instability.
- To explore its impact on electron dynamics and current sheet structure.
- To assess the subsequent effects on magnetic reconnection onset.
Main Methods:
- Fully kinetic particle-in-cell simulations.
- Simulations included ion-to-electron mass ratios up to m(i)/m(e)=1836.
- Analysis focused on electron flow velocity, current density, and particle heating.
Main Results:
- The lower-hybrid drift instability, though localized at the edge, drives significant electron flow in the center.
- A strong bifurcation of current density and anisotropic electron heating were observed.
- These nonlinear effects dramatically enhance the collisionless tearing mode instability.
Conclusions:
- The simulated lower-hybrid drift instability can trigger rapid magnetic reconnection in critical-scale current sheets.
- Electron dynamics play a crucial role in mediating the transition to reconnection.
- These findings have implications for understanding energy dissipation in astrophysical and laboratory plasmas.