Electron Weibel instability induced magnetic fields in optical-field ionized plasmas

Abstract: Generation and amplification of magnetic fields in plasmas is a long-standing topic that is of great interest to both plasma and space physics. The electron Weibel instability is a well-known mechanism responsible for self-generating magnetic fields in plasmas with temperature anisotropy and has been extensively investigated in both theory and simulations, yet experimental verification of this instability has been challenging. Recently, we demonstrated a new experimental platform that enables controlled initialization of highly nonthermal and/or anisotropic plasma electron velocity distributions via optical-field ionization. Using an external electron probe bunch from a linear accelerator, the onset, saturation, and decay of the self-generated magnetic fields due to electron Weibel instability were measured for the first time to our knowledge. In this paper, we will first present experimental results on time-resolved measurements of the Weibel magnetic fields in non-relativistic plasmas produced by Ti:Sapphire laser pulses (0.8 μm) and then discuss the feasibility of extending the study to a quasi-relativistic regime by using intense CO2 (e.g., 9.2 μm) lasers to produce much hotter plasmas.

Recommended citation: Chaojie Zhang, Yipeng Wu, Mitchell Sinclair, Audrey Farrell, Kenneth A. Marsh, Jianfei Hua, Irina Petrushina, Navid Vafaei-Najafabadi, Rotem Kupfer, Karl Kusche, Mikhail Fedurin, Igor Pogorelsky, Mikhail Polyanskiy, Chen-Kang Huang, Wei Lu, Warren B. Mori, Chan Joshi, "Electron Weibel instability induced magnetic fields in optical-field ionized plasmas," Phys. Plasmas 29, 062102 (2022).
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