Transverse phase space diagnostics for ionization injection in laser plasma acceleration using permanent magnetic quadrupoles. (22nd February 2018)

• Record Type: Journal Article
• Authors: Li, F; Nie, Z; Wu, Y P; Guo, B; Zhang, X H; Huang, S; Zhang, J; Cheng, Z; Ma, Y; Fang, Y; Zhang, C J; Wan, Y; Xu, X L; Hua, J F; Pai, C H; Lu, W; Mori, W B
• Is Part Of: Plasma physics and controlled fusion. Volume 60:Number 4(2018:Apr.)
• Publication Date: 2018-02-22
• Subjects: emittance -- phase space -- Twiss parameter -- permanent magnetic quadrupole -- laser plasma accelerator; 52.38.Kd -- 41.75.Jv -- 52.35.Mw; Plasma (Ionized gases) -- Periodicals; Controlled fusion -- Periodicals; 530.44
• DOI: 10.1088/1361-6587/aaacc2
• Languages: English
• ISSNs: 0741-3335

Abstract

Abstract: We report the transverse phase space diagnostics for electron beams generated through ionization injection in a laser-plasma accelerator. Single-shot measurements of both ultimate emittance and Twiss parameters are achieved by means of permanent magnetic quadrupole. Beams with emittance of μ m rad level are obtained in a typical ionization injection scheme, and the dependence on nitrogen concentration and charge density is studied experimentally and confirmed by simulations. A key feature of the transverse phase space, matched beams with Twiss parameter α T ≃ 0, is identified according to the measurement. Numerical simulations that are in qualitative agreement with the experimental results reveal that a sufficient phase mixing induced by an overlong injection length leads to the matched phase space distribution.