Investigation of magnetic reconnection under a strong guide field

Magnetic reconnection under a strong guide field with B_G/B₀>>1 is investigated using the gyrokinetic electron and fully-kinetic ion (GeFi) particle simulation model, where B_G and B₀ are the guide and the anti-parallel component of magnetic field, respectively. The simulation is carried out for a force free current sheet. The GeFi schemes can adopt a realistically small ion-to-electron mass ratio m_i/m_e to study physics issues covering a broad frequency range of interest for space and laboratory plasmas. Cases with various m_i/m_e are presented in order to understand the effects of the mass ratio on the structures of reconnection. Secondary instabilities are found in the separatrix region of the primary reconnection. Effects of the mass ratio and guide field strength on the generation of the secondary instabilities are illustrated.