Rogue waves detection in ion acoustic turbulence inside a new toroidal plasma device

The appearance of rogue waves in turbulence has recently attracted much interest in neutral and conducting fluids. This is of major importance in nonlinear dynamics research. We propose to detect very large amplitude solitary waves in ion acoustic turbulence excited in an ion-beam plasma system. Numerical studies have been performed recently by several authors in the case of rogue waves in dusty plasmas (1,2). Our experiment is conducted in a new toroidal unmagnetized plasma device (rr= 40 cm, R=60 cm). The plasma is created by thermionic emission using hot tungsten filaments. The ionizing electrons are confined inside the torus by a multipolar magnetic structure (3) arranged in a “checkerboard” configuration of permanent magnets glued on the external wall of the toroidal vessel. Grids inserted in the plasma create the counter-propagating ion beams exciting the turbulence when the relative velocity of the ions is larger than the ion acoustic velocity. The detection of rare large events is performed in real-time using a digital storage oscilloscope. Preliminary results are presented.

1- N. Kaur et al., Plasma Sci. & Technology, 20, 074009, 2018.

2- K. He et al., Physics Letters A, 378, 2137, 2014.

3- K. N. Leung, N. Hershkowitz, K. R. MacKenzie, Phys. Fluids, 19, 1045, 1976.