Diagnosis of Weibel instability evolution in the rear surface density scale lengths of laser solid interactions via proton acceleration

Scott, G. G.; Brenner, C. M.; Bagnoud, V.; McKenna, P.; Zielbauer, B.; Powell, H. W.; Green, J. S.; Neely, D.; Rusby, D. R.; Gonzalez-Izquierdo, B.; Clarke, R. J.; Heathcote, R. I.

doi:10.1088/1367-2630/aa652c

Journal Article

GSI-2017-00625

Diagnosis of Weibel instability evolution in the rear surface density scale lengths of laser solid interactions via proton acceleration

Scott, G. G. (Corresponding author) ; Brenner, C. M. ; Bagnoud, V.GSI* ; Clarke, R. J. ; Gonzalez-Izquierdo, B. ; Green, J. S. ; Heathcote, R. I. ; Powell, H. W. ; Rusby, D. R. ; Zielbauer, B.GSI* ; McKenna, P. ; Neely, D.

2017
Dt. Physikalische Ges. [Bad Honnef]

New journal of physics 19(4), 043010 (2017) [10.1088/1367-2630/aa652c]

This record in other databases:

Please use a persistent id in citations: doi:10.1088/1367-2630/aa652c doi:10.15120/GSI-2017-00625

Abstract: It is shown for the first time that the spatial and temporal distribution of laser accelerated protons can be used as a diagnostic of Weibel instability presence and evolution in the rear surface scale lengths of a solid density target. Numerical modelling shows that when a fast electron beam is injected into a decreasing density gradient on the target rear side, a magnetic instability is seeded with an evolution which is strongly dependent on the density scale length. This is manifested in the acceleration of a filamented proton beam, where the degree of filamentation is also found to be dependent on the target rear scale length. Furthermore, the energy dependent spatial distribution of the accelerated proton beam is shown to provide information on the instability evolution on the picosecond timescale over which the protons are accelerated. Experimentally, this is investigated by using a controlled prepulse to introduce a target rear scale length, which is varied by altering the time delay with respect to the main pulse, and similar trends are measured. This work is particularly pertinent to applications using laser pulse durations of tens of picoseconds, or where a micron level density scale length is present on the rear of a solid target, such as proton-driven fast ignition, as the resultant instability may affect the uniformity of fuel energy coupling.

Classification:

ddc:530

Note: "Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. "

Contributing Institute(s):