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Yearly Archives: 2019
From 27th October to 4th November 2019 Ivke visited NIFS (National Institute for Fusion Science) in Toki, Japan, as a member of University of Belgrade delegation headed by rector Ivanka Popović, who signed an Agreement of collaboration between NIFS and University of Belgrade.
Ivke, Bratislav Obradović (Faculty of Physics), Milan Rajković (Institute of Nuclear Sciences Vinca) and Milica Ilić (Faculty of Mechanical Engineering) had a fruitful discussions with Japanese colleagues and made plans for future common projects.
On 23rd October 2019, our Laboratory member Marko Cvejić held an open lecture at the Institute of Physics Belgrade. The lecture was “Challenges in the investigation of compression of magnetized plasma“, where he presented his results obtained at the Weizmann Institute of Science.
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 . 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.
 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).
- ELI attosecond in Szeged (HU);
- High voltage laboratory in Brno (CZ), where they work with 120 kA currents and 2 MV voltages;
- Helmholtz‐Zentrum Dresden‐Rossendorf in Dresden (D) seeing Ion Beam Facility and Radiation Source ELBE;
- ELI beams and Institute of Plasma Physics in Prague (CZ), latter one showed him COMPASS tokamak and PALS ion laser.
Miloš‘ previous work during the PhD research has payed off. The article on “Runaway electron beam stability and decay in COMPASS” has been published in Nuclear Fusion journal.
Since 1st March 2019, Marijana has new role as Assistant Professor (“docent” in Serbian) at the Faculty of Engineering, University of Kragujevac. But above all, we are happy that she is going to stay the part of our team despite new obligations.
She gave a lecture entitled “Uncovering Beryllium line with forbidden component”:
>>> MISSING PHOTO (waiting for organizors) <<<
She also obtained an Award Certificate for complimentary registration for the next year conference edition in Tucson, AR (USA):
For more details visit the following link.
We are proudly presenting published article as a proceeding of the SPIG conference by Miloš. The article is entitled “Experimental Runaway Electron Current Estimation in COMPASS Tokamak” and published by Atoms journal.