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AKBP: Arbeitskreis Beschleunigerphysik

AKBP 6: New Accelerator Concepts - Models and Experiments

AKBP 6.5: Talk

Tuesday, March 19, 2024, 12:00–12:15, E 020

Searching for non-thermal acoustic pulses emitted from laser-produced plasmas in water — •Timo Pohle, Anna-Katharina Schmidt, Julia Liese, and Jörg Schreiber — Fakultät für Physik, Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748 Garching

Laser acceleration in plasmas can yield short, very dense bunches of protons and heavier ions, which complicates diagnosing them. We use water as a detector medium where the ions deposit their energy when slowing down without the risk of destroying the detector. The rapid change in energy density results in an acoustic wave that provides a way of characterizing each ion bunch individually. Modeling the process commonly relies on the thermoacoustic approach, that is water thermally expands due to local heating. Surprisingly, heating by ions creates an additional, non-thermoacoustic, signal component which becomes observable close to the temperature where water has its highest density. In contrast, heating due to linear absorption of light behaves thermally [1]. We are now measuring the acoustic signal created by a laser produced plasma and by ions depositing their energy using water of around 4^∘C. This suppresses the thermoacoustic contribution and enables us to investigate the origin of the non-thermal signal. In my talk I will present first experimental results of the plasma-acoustic experiments.

[1] R. Lahmann et al. Astropart. Phys. 65, 69 (2015).

Keywords: ionoacoustics; laser induced plasma; laser ion acceleration; Ion Bunch Energy Acoustic Tracing