Probing thermal Weibel instability in optical-field-ionized plasmas using relativistic electron bunches

Journal Article · 08 January 2020 · Plasma Physics and Controlled Fusion

DOI: https://doi.org/10.1088/1361-6587/ab61e0 · OSTI ID:1737410

Zhang, Chaojie  ^[1]; Huang, Chen-Kang  ^[2]; Marsh, Ken A. ^[2]; Joshi, Chan ^[2]

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1. Univ. of California, Los Angeles, CA (United States); UCLA
2. Univ. of California, Los Angeles, CA (United States)

Thermal Weibel instability driven by anisotropic velocity distributions is an important mechanism for self-generating magnetic fields in both laboratory and space plasmas. However, there is a lack of experimental data on thermal Weibel instability due to the difficulty of initializing anisotropic distributions in a controllable manner as well as the challenge of probing the magnetic fields with high spatiotemporal resolution. Here we show that the initial electron velocity distribution of optical-field-ionized plasmas can be easily manipulated by changing laser polarization and such plasmas are unstable to the thermal Weibel instability. The topology of the self-generated magnetic fields depends on the laser polarization. Here, we propose to use ultrashort relativistic electron beams such as those produced by a laser wakefield accelerator as a probe to record the spatiotemporal evolution of the magnetic fields. By taking a series of snapshots of the magnetic fields at different times, the wavevector spectrum and growth rate of the instability can be deduced and compared with kinetic theory.

• Research Organization: Univ. of California, Los Angeles, CA (United States)
• Sponsoring Organization: NSF; USDOE
• Grant/Contract Number: SC0010064
• OSTI ID: 1737410
• Journal Information: Plasma Physics and Controlled Fusion, Journal Name: Plasma Physics and Controlled Fusion Journal Issue: 2 Vol. 62; ISSN 0741-3335
• Publisher: IOP ScienceCopyright Statement
• Country of Publication: United States
• Language: English