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

• Published in: arXiv.org 2022-04
• Main Authors: Zhang, Chaojie, Wu, Yipeng, Sinclair, Mitchell, Farrell, Audrey, Marsh, Kenneth A, Hua, Jianfei, Petrushina, Irina, Vafaei-Najafabadi, Navid, Kupfer, Rotem, Kusche, Karl, Fedurin, Mikhail, Pogorelsky, Igor, Polyanskiy, Mikhail, Chen-Kang, Huang, Lu, Wei, Mori, Warren B, Joshi, Chan
• Format: Article
• Language: English
• Subjects: Anisotropy; Electron probes; Feasibility studies; Field ionization; Magnetic fields; Plasmas (physics); Relativistic effects; Relativistic plasmas; Sapphire; Time measurement; Weibel instability
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2204.04262

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 the 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 \(\mu m\)) and then discuss the feasibility of extending the study to quasi-relativistic regime by using intense \(\rm CO_2\) (e.g., 9.2 \(\mu m\)) lasers to produce much hotter plasmas.