[institut] Seminar: Marko Cvejic Wednsday 23.10 at 12:00

[Milivoje Ivkovic]

Dear colleagues,

You are cordially invited to the seminar of the PSL (Plasma Spectroscopy 
and Lasers)laboratory ,
which will be held on Wednesday, 23 October 2019 at 12:00
in the library reading room “Dr. Dragan Popović" of the Institute of 
Physics Belgrade.

The talk entitled

Challenges in the investigation of compression of magnetized plasma

will be given by Marko Cvejić,
(present address: Weissman Institute of Physical Sciences. Rehovot 
76100, Israel

Abstract

The seminar will refer to a compression of magnetic flux that is 
initially embedded in a plasma that undergoes an implosion. The plasma 
is produced in a Z-pinch configuration in which a gas puff load is 
ionized and implodes under the J×B forces resulting from a 1-μs long, 
300 kA, current pulse.
The subject of compression of magnetic flux and magnetized plasma is a 
fundamental problem manifested in a variety of conducting fluid 
phenomena in laboratory plasmas and astrophysics. Recently, this subject 
has gained particular interest due to the advances in producing plasmas 
of high temperature and density for fusion purposes, based on the 
approach of magnetized plasma compression.
We report the first-time development and employment of spectroscopic 
methods, based on the Zeeman effect and polarization techniques, to 
measure both the compressed (axial) and the compressing (azimuthal) 
magnetic fields throughout the implosion and stagnation processes. Time 
and space resolved spectroscopic measurements showed that the 
application of a relatively weak axial magnetic field (Bz0) has a 
dramatic effect on the implosion dynamics affecting significantly the 
current distribution in the plasma [1]. It was found that in the 
presence of Bz a large part of the current does not flow in the 
imploding plasma, rather it flows through a slow-imploding low-density 
plasma (LDP) residing at large radii. Furthermore, it is observed that 
the fraction of total current that flows in the LDP increases with Bz0. 
We suggest an explanation of the phenomena, based on the development of 
a force-free current configuration.
Previously unpredicted observations in high-power magnetized-plasma 
experiments, including recent unexplained structures observed in the 
Magnetized Liner Inertial Fusion experiment, may be connected to the 
present discovery.
[

1] Mikitchuk, D., Cvejić, M., Doron, R., Kroupp, E., Stollberg, C., 
Maron, Y., Velikovich, A. L., Ouart, N. D., Giuliani, J. L., Mehlhorn, 
T. A., Yu, E. P., and Fruchtman, A. “Effects of a preembedded axial 
magnetic field on the current distribution in a Z-pinch implosion”, 
Phys. Rev. Lett. 122, 045001 (2019).

Best regards,
Milivoje Ivković


-- 
Milivoje Ivkovic
Research Professor
Head of Plasma Spectroscopy and Lasers laboratory
Institute of Physics Belgrade, University of Belgrade
Pregrevica 118, 11080 Belgrade, Serbia
http://www.ipb.ac.rs/
http://psl-lab.ipb.ac.rs/