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Microwave Breakdown by Time Reversal

par Laurence Laffont - publié le , mis à jour le

Valentin MAZIÈRES’ thesis defense intitled "Microwave Breakdown by Time Reversal" will be taking place on November, 27th, 2020 at 9:30 am by visioconference.

His work has been supervized by par Olivier Pascal, Romain Pascaud, Laurent Liard, Simon Dap as well as Richard Clergereaux.

Jury :

Mr Olivier PASCAL - Paul Sabatier University - Thesis director
Mr Romain PASCAUD - ISAE - Thesis co-director
Mrs. Élodie RICHALOT - Paris-Est Marne-la-Vallée University - Reviewer
Mrs. Kremena MAKASHEVA - Paul Sabatier University - Reviewer
Mr Julien DE ROSNY - Langevin Institute - Rapporteur
Mr Jean Paul BOOTH - Laboratoire de Physique des Plasmas - Rapporteur
Mr Laurent LIARD - Paul Sabatier University - Reviewer
Mr Philippe POULIGUEN - DGA/AID - Reviewer
Mr Christophe CALOZ - KU Leuven - Guest

Zoom :

Topic : Soutenance Thèse Valentin MAZIERES
Time : nov. 27th 2020 09:30 AM Paris

Participate :

ID : 834 0009 5274

The visioconference will be open from 9:15 am. Please mind swithching off both your microphone and camera.

Abstract :

Plasmas’ physical properties allow various and interesting applications, such as exploiting their light properties (neon…), as exploiting their interaction with materials (surface treatment…) as well as accelerating charge particles to put into motion a satellite.
Plasma generation requires transfering a certain energy in to a gaz, whether in the form of heat or of electricity. In the latter case, the use of microwaves is particularly interesting. Generally speaking, the microwave energy transfer to the electrons is done by exploiting the ability of the resonant cavities in order to intensify the electric field or by wave absorption.
In all of these cases, the plasma’s position is fixed by the system design. This last point is a limitation of these devices, meaning they are not at all versatile in term of spatio-temporal control of the plasma.
It is however possible to use more elaborated techniques, by working on the waveform of the feeding signal. In cavities, this waveform determines the behavior of the waves. Then, by smartly manipulating it, it is possible to significantly improve the control of the plasmas in cavities. The wave control technique that appears the most obvious to meet that objective is Time Reversal, which allows spatio-temporally focusing the electromagnetic energy. The aim of this PHD is to use Time Reversal to locally transfer some energy into the electrons and, by doing so, generate a local plasma, like a “plasma brush”. In this case, modifying the waveform of the signal transmitted to the cavity will allow to control the position of the plasma into the cavity, disrespectuously to the cavity design. Furthermore, the larger the cavity, the better control will occur. The results obtained during this thesis are the first plasmas ever initiated by Time Reversal.

Key-words :
Plasma source, Time Reversal, Microwave reverberant cavity, Nanosecond plasma