Sub-Alfvenic Expansion of Spherical Laser-Produced Plasma: Flutes, Cavity Collapse and Field-Aligned Jets

The laboratory experiment on modeling a sub-Alfvénic interaction of expanding plasma cloud with vacuum magnetic field is described. We produce spherically symmetric cloud by 4-beam laser irradiation of the pellet. The presented data reveal complex dynamic of cloud deceleration and formation of two field aligned jets, development of the flute instability and rapid collapse of the diamagnetic cavity. It is shown that cavity collapse can’t be explained by plasma motion or anomalous diffusion and requires for explanation a new mechanism.