Direct Measurement of the Return Current Instability in a Laser-Produced Plasma

This is the authors' abstract. We don't add key points for this paper.

Measurements were made of the return current instability growth rate, demonstrating its concurrence with nonlocal transport. Thomson scattering was used to measure a maximum growth rate of 5.1×10⁹ Hz, which was 3 times less than classical Spitzer-Härm theory predicts. The measured plasma conditions indicate the heat flux was nonlocal, and Vlasov-Fokker-Planck simulations that account for nonlocality reproduce the measured growth rates. Furthermore, the threshold for the return current instability was measured (δT=0.017±0.002) to be in good agreement with previous theoretical models.