Time Evolution of Kelvin–helmholtz Vortices Associated With Collisionless Shocks in Laser-Produced Plasmas

Abstract

We report experimental results on Kelvin-Helmholtz (KH) instability and resultant vortices in laser-produced plasmas. By irradiating a double plane target with a laser beam, asymmetric counterstreaming plasmas are created. The interaction of the plasmas with different velocities and densities results in the formation of asymmetric shocks, where the shear flow exists along the contact surface and the KH instability is excited. We observe the spatial and temporal evolution of plasmas and shocks with time-resolved diagnostics over several shots. Our results clearly show the evolution of transverse fluctuations, wavelike structures, and circular features, which are interpreted as the KH instability and resultant vortices. The relevant numerical simulations demonstrate the time evolution of KH vortices and show qualitative agreement with experimental results. Shocks, and thus the contact surfaces, are ubiquitous in the universe; our experimental results show general consequences where two plasmas interact.

Large-area suspended graphene as a laser target to produce an energetic ion beam

“…We have worked on the so-called laboratory astrophysics, where space and astrophysical phenomena are experimentally simulated in laboratories with high-power lasers, such as plasma jet [1][2][3][4] , collisionless shocks [5][6][7][8][9][10] and hydrodynamic instabilities [11,12] . We recently extended our research field to include the relativistic regime of laboratory astrophysics with intense laser pulses [13][14][15] .…”