Sprecher
Beschreibung
In this contribution, we present results of an extensive study of LWFA driven by ATLAS-3000 at CALA in Garching, yielding GeV-scale electrons. By monitoring numerous laser and electron diagnostics in parallel during LWFA experiments at a 0.25 Hz repetition rate, we find that, among all parameters monitored, the laser wavefront exhibits the highest correlation with electron energy. The largest contribution to this correlation stems from fluctuations in the defocus coefficient, which display a very similar dynamics to the electron energy fluctuations on a time scale of minutes.
We additionally report on efforts to search for the origin of the defocus variations in the behavior of the temperature distribution of the main amplifier crystal and on the effects of lowering the overall crystal temperature by enhancing its cooling system. Our observations raise the question to which extent the laser wavefront in petawatt laser systems can be passively stabilized or whether active wavefront correction becomes practically inevitable when aiming for stable LWFA operation driven by laser pulses exceeding the 10 J-level.
