Topic/Type: 1. Plasma Simulation, Oral

Multi-hierarchy physics in collisionless driven reconnection

R. Horiuchi1, 2, S. Usami1, H. Ohtani1, 2, M. Den3

1 National Institute for Fusion Science, Toki 509-5292, Japan
2 The Graduate University for Advanced Studies, Toki 509-5292, Japan
3 National Institute of Information and Communications Technology, Koganei 184-8795, Japan

In order to investigate full picture of magnetic reconnection controlled by multi-hierarchy physics from microscopic physics relating to electron and ion dynamics through macroscopic one such as plasma transport in a global scale, we have developed two kinds of numerical simulation models. One is the electromagnetic particle model for an open system (?PASMO?). A series of particle simulations using the PASMO code have revealed new features of microscopic physics of collisionless reconnection in open systems. The growth of pressure tensor and formation of non-Maxwellian distribution function in the central current layer demonstrate that the meandering orbit effect play a crucial role in triggering collisionless reconnection [1,2].
The other is multi-hierarchy simulation model for magnetic reconnection, which consists of three parts, i.e., MHD model to describe global dynamics of reconnection phenomena, PIC model to describe the microscopic processes in the vicinity of reconnection point, and interface model to describe the interaction between micro and macro hierarchies [3,4]. The model is applied to a few numerical test programs and collisionless driven reconnection in a simple geometry and is confirmed to work well. We will describe the details of simulation model and obtained new features of collisionless driven reconnection in our presentation.

[1] A. Ishizawa and R. Horiuchi, ?Suppression of Hall-Term Effects by Gyroviscous Cancellation in Steady Collisionless Magnetic Reconnection?, Physical Review Letters, Vol.95 (2005) pp. 045003-1-045003-4

[2] R. Horiuchi and H. Ohtani, ?Formation of non-Maxwellian distribution and its role in collisionless driven reconnection?, Communications in Computational Physics, Vol. 4 (2008) pp. 496-505.

[3] S.Usami, H. Ohtani, R. Horiuchi, and M. Den, ?Development of Multi-hierarchy Simulation Model for Studies of Magnetic Reconnection?, Communications in Computational Physics, Vol. 4 (2008) pp. 537-544.

[4] R. Horiuchi, H. Ohtani, and A. Ishizawa, ?Towards cross-hierarchy simulation of collisionless driven reconnection in an open system?, J. Plasma Phys., Vol. 72, No.6 (2006) pp. 953-956.