Giant ElectroMagnetic Pulse generation in short pulse laser experiments
| Quand ? |
Le 15/03/2016, de 10:45 à 12:00 |
|---|---|
| Où ? | Centre Blaise Pascal |
| Participants |
Alexandre Poyé |
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A continuous progress in increasing the laser intensity opens new domains of physics and applications from inertial confinement fusion to laboratory astrophysics and material processing. However, interaction of intenses laser pulses with matter is accompanied with the side effect called Giant ElectroMagnetic Pulse (GEMP). This is an electromagnetic pulse in the GHz domain that propagates inside the interaction chamber with an amplitude,which can reach the MV/m level [1, 2], as measured on the Omega EP laser facility. The physics of this phenomena can be summarized as follow [3, 4]. The laser accelerates target electrons, which may escape from the target. A neutralization current comes from the target holder, which acts like an antenna and emits GEMP. The target charge is then the energy source of GEMP and the holder is shaping the frequencies and the directivity of the emission.
The emitted magnetic field and the target charge were measured in a dedicated experiment on the Eclipse facility. We found a linear relation between the charge and the GEMP amplitude independently of the target material and the laser parameters. The comparison of the experiment and a new quantitative model will be presented [5].
[1] M.J. Mead et al., Rev. Sci. Instrum. 75, 4225 (2004)
[2] C.G. Brown Jr. et al., J. Phys. Conf. Ser. 112, 032025 (2008)
[3] J.-L. Dubois et al., Phys. Rev. E 89, 013102 (2014)
[4] A. Poyé et al., Physical Review E 91, 043106 (2015)
[5] A. Poyé et al., Physical Review E 92, 043107 (2015)