Measurements of the growth and saturation of electron Weibel instability in optical-field ionized plasmas
Published in Physical Review Letters, 2020
Abstract: The temporal evolution of the magnetic field associated with electron thermal Weibel instability in optical-field ionized plasmas is measured using ultrashort (1.8 ps), relativistic (45 MeV) electron bunches from a linear accelerator. The self-generated magnetic fields are found to self-organize into a quasistatic structure consistent with a helicoid topology within a few picoseconds and such a structure lasts for tens of picoseconds in underdense plasmas. The measured growth rate agrees well with that predicted by the kinetic theory of plasmas taking into account collisions. Magnetic trapping is identified as the dominant saturation mechanism.
Impact: This work extends the FREP concept to using ps electron bunches from linear accelerators as a probe to capture not-so-transient magnetic fields. It provides direct measurements of Weibel instability dynamics, fundamental to understanding plasma physics in laboratory astrophysics contexts.
Recommended citation: Chaojie Zhang, Jianfei Hua, Yipeng Wu, Yu Fang, Yue Ma, Tianliang Zhang, Shuang Liu, Bo Peng, Yunxiao He, Chen-Kang Huang, Ken A. Marsh, Warren B. Mori, Wei Lu, Chan Joshi, "Measurements of the growth and saturation of electron Weibel instability in optical-field ionized plasmas," Phys. Rev. Lett. 125(25), 255001 (2020).
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