Dynamics of guided post-acceleration of protons in a laser-driven travelling-field accelerator. (12th October 2020)

• Record Type: Journal Article
• Authors: Hadjisolomou, P; Ahmed, H; Prasad, R; Cerchez, M; Brauckmann, S; Aurand, B; Schroer, A M; Swantusch, M; Willi, O; Borghesi, M; Kar, S
• Is Part Of: Plasma physics and controlled fusion. Volume 62:Number 11(2020)
• Publication Date: 2020-10-12
• Subjects: laser -- proton -- post-acceleration -- helical coil; Plasma (Ionized gases) -- Periodicals; Controlled fusion -- Periodicals; 530.44
• DOI: 10.1088/1361-6587/abb91a
• Languages: English
• ISSNs: 0741-3335

Abstract

Abstract: By directing the laser-driven electromagnetic pulses along a helical path, one can achieve a travelling-field accelerator arrangement for simultaneous beam shaping and re-acceleration of laser-accelerated protons. The dynamics of guided acceleration of the transiting protons was studied by varying the length of the helical coil. Experimental data shows that the protons co-moving with the field region exhibit stronger focussing while increasing the coil length, with an increase of kinetic energy due to simultaneous post-acceleration. The net energy gain for a coil of constant pitch however saturates eventually when the post-accelerated protons overtakes the accelerating field region in due course. 3D particle tracing simulation underpins the dynamics of beam transport inside the coil, which highlights the requirement for a variable pitch coil geometry in order to sustain the post-acceleration over an extended coil.