CUOS Noon Seminar: Jon Murphy and Hongmei Tang

Jon Murphy: Filamentation compression of CPA laser pulses and beam applications

Compression of amplified laser pulses beyond the limits of a compressor grating-setup has been a fruitful topic of research for decades. Filamentation compression offers a solution which benefits from a higher energy capacity and being easier to couple light into than the the hollow-core fiber compression scheme. Here, 40 fs CPA laser pulses with 40 nm FWHM bandwidth are spectrally-broadened and compressed. An experimental analysis of the post-filamented beam’s spatial profile, spectrum, and pulse length is presented. Also included is a review of various appropriate applications for this beam in a few laser-plasma interaction experiments including K-alpha x-ray generation and LWFA. The effect of pulse duration on x-ray generation in recent LasernetUS experiments is also described.

Hongmei Tang: A High-Intensity Laser Pulse Interactions with an Underdense Plasma: Electron Acceleration and Channel Formation

High-intensity picosecond laser pulses interacting with underdense plasma are capable of generating superponderomotive electrons with energies up to hundreds of MeV, as well as secondary particles and radiation. Direct Laser Acceleration (DLA), the main laser-particle energy transfer mechanism in the regime we are studying, requires channel formation. A number of secondary dynamic processes and instabilities occur during the interaction and are not fully understood. To have better insight into these complex processes, we performed experiments on the OMEGA EP facility using apodized beams and 2D particle-in-cell simulations using OSIRIS. The combination of experimental measurements and the simulation results reveal the dynamics of electrons and field evolution. Our research shows the dependency of DLA on different plasma and laser parameters.

Pizza will be served!