Controlling the Self-Injection Threshold in Laser Wakefield Accelerators.
Phys Rev Lett
; 121(15): 154801, 2018 Oct 12.
Article
em En
| MEDLINE
| ID: mdl-30362794
ABSTRACT
Controlling the parameters of a laser plasma accelerated electron beam is a topic of intense research with a particular focus placed on controlling the injection phase of electrons into the accelerating structure from the background plasma. An essential prerequisite for high-quality beams is dark-current free acceleration (i.e., no electrons accelerated beyond those deliberately injected). We show that small-scale density ripples in the background plasma are sufficient to cause the uncontrolled (self-)injection of electrons. Such ripples can be as short as â¼50 µm and can therefore not be resolved by standard interferometry. Background free injection with substantially improved beam characteristics (divergence and pointing) is demonstrated in a gas cell designed for a controlled gas flow. The results are supported by an analytical theory as well as 3D particle in cell simulations.
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MEDLINE
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En
Ano de publicação:
2018
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Article