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Astrophysical Seminar (20 April 2017, 11:00)

Опубликовано: 13/04/2017

1) Speaker: M.V. Starodubtsev (IAP RAS, Nizhny Novgorod)

Title: "Plasma Physics and Particle Acceleration Studies at the PEARL Laser Facility"

Abstract:

The experimental results on the laser-driven proton acceleration using a femtosecond laser pulse with the maximal power up to 170 TW (< 8 J, 60 fs) focused by a F/4 off-axis parabola in the focal spot of 6 um diameter on the surface of a thin aluminum target (whose thickness varied from 0.5 to 10 um). The target has been oriented at 45 degree with respect to the laser axis. The intensity of the laser radiation in the focal spot reached up to 3e20 W/cm2. TNSA (target normal sheath acceleration) was the main regime of proton acceleration in our experiments was. In this regime, protons are accelerated by the electrostatic field due to space charge separation caused by the heating of the target electrons by the laser radiation. During the experiments, energies of the accelerated proton achieved more than 43 MeV, which is a record value for the laser systems with output energy less than 20 Joules.

Another field of research at the PEARL laser facility is the laboratory modeling of astrophysical problems. We studied the coupling of a high-amplitude and large-scale magnetic field to high-velocity plasma flows in order model the magnetohydrodynamic processes in the vicinity of accreting astrophysical systems. In the course of this work we studied the physical processes in the boundary layer between the moving plasma with a magnetic field, which is a key factor for the development of physical models of different astrophysical objects, such as accretion disks, accretion columns, astrophysical jets etc. The experimental results modeling the accretion processes on the magnetized astrophysical objects are presented.

 

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