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ELFIE - Pursuing the investigation of the streaming instability in the laboratory (J. Fuchs)

This proposal aims at pursuing the investigation of the development of the streaming instability that we have started to undertake this year during a first experiment performed at the ELFIE laser facility. The streaming instability is driven by energetic ions propagating in a magnetized background plasma. Our goal is to elucidate the effects of the instability on the ion beam and background plasma. Beyond its interest as a fundamental phenomenon in plasma physics, electromagnetic streaming instabilities play a key role in the acceleration of particles in astrophysical shocks and are also recognized to be responsible for confining low energy cosmic rays, both effect have potentially important repercussion on the observed anomalous ionization of dense clouds in the inter-stellar medium (ISM), and thus on star formation.
Exploiting the coupling between fast ion beams driven by short-pulse lasers, the generation and characterization of well-controlled background plasma in which the ions will be propagated, and strong external magnetization of this system, we have this year observed very clear collisionless ion energy losses in magnetized plasmas for broadband energy ion beams. Strong thermalization of streaming ion beams are also observed in numerical investigations we are pursuing in parallel using hybrid codes, and which will be refined in the conditions of the experiment. The present proposal aims at going beyond this first observation by better diagnosing the interaction conditions, as well as investigating thee case of “cold” ion beam, i.e. having narrow energy distributions.

ELFIE - S12-16 / 2018