Particle Physics Seminar: The Onset of Uninhibited Heat Conduction and of Non-Local Absorption in Flux-Limited Laser-Plasma Ablation

Matan Ben Dov, TAU

14 January 2021, 10:00 
Zoom: https://us02web.zoom.us/j/83283854432?pwd=VXdmZ1lTbkl4SEZnVndqcUZNQWg0UT09&from=msft 
Particle Physics Seminar

Zoom: https://us02web.zoom.us/j/83283854432?pwd=VXdmZ1lTbkl4SEZnVndqcUZNQWg0UT09&from=msft

 

Abstract:

The interaction of high energy laser pulses with plasma is a complex physical process.  It involves light propagation and absorption through a target, heat-conduction, and hydrodynamic flow. The resulting plasma conditions depend on the incoming laser-flux and on the target material and geometry. 
A complete physical description of the ablation process requires heavy computation; often deeming it impractical. This motivates the formulation of approximated models which are valid for specific plasma flow properties: e.g. plasmas featuring near-critical laser absorption in the presence of classical heat conduction or flux-limited conduction and  involving inverse-bremsstrahlung absorption.
In my talk, I will address the following challenge: for a given ablation conditions, how can one ascertain the basic flow properties in advance, so the appropriate approximation may be chosen? 
I will present an analytical investigation of how the temperature profile evolves with time, and validation of the results using a numerical investigation.
I will show through dimensional analysis that the temperature in the resulting corona and conduction zones is characterized by scaling relations through 3 dimensional and 2 dimensionless parameters.
The results form a phase diagram for the behaviors of the maximal temperature as a function of time at different phases of the flow.
Measured experimentally, the identified transition times can be used to infer the characteristic value of the flux-limiter.

 

 

 

Seminar Organizers: Prof. Erez Etzion & Dr. Liron Barak

 

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