Laboratory and PIC simulations of collisionless interaction between expanding space plasma clouds and magnetic field with and without ionised background

Abstract
Experiments on flute instability of plasma clouds at Alfven Mach-number Ma 0 and 1, and with varying ion's magnetization level have been realized at the KI-1 laser-plasma facility at the ILP of Novosibirsk, with similarity parameters close to those of Barium releases in Earth's magnetosphere. A number of diagnostics have allowed to characterize the dynamics of the cloud-magnetic field interaction, as well as flutes development, or suppression for Ma > 1. Hybrid simulations with HAWAI2D code have reproduced the main observed features, such as the diamagnetic cavity dynamics, and flutes growth. A mode-mixing phenomenon related to Larmor rotation has been observed in simulations, which seems to lead to a reduction of mode number at later times in agreement with experimental results.