28–30 Nov 2011
Laboratori Nazionali di Frascati <!-- ID_UTENTE=505 -->
Europe/Rome timezone

Two-pulse Thomson Scattering System for Measurements of Fast Fluctuation of Electron Density Profile in Multi-Mirror trap GOL-3

29 Nov 2011, 14:56
1m
Aula Bruno Touschek (Building 36): <a target= (Laboratori Nazionali di Frascati <!-- ID_UTENTE=505 -->)

Aula Bruno Touschek (Building 36): <a target=

Laboratori Nazionali di Frascati <!-- ID_UTENTE=505 -->

Via E. Fermi, 40

Speaker

Dr Sergei Popov (Budker Institute of Nuclear Physics)

Description

At the GOL-3 set up in BINP experiments on studying the relaxation mechanism of a powerful relativistic electron beam, and plasma confinement in multimirror magnetic field are carried out. At present, the mechanisms of generation of microwave radiation in plasma with Langmuir turbulence are investigated. An important place in these studies is the observation of the dynamics of plasma density in the spatial and temporal scales typical for turbulent processes. These include the modulation instability and Langmuir collapse observed in beam-plasma experiments [1]. Characteristic time scale in similar plasma [1] can be reach order of 10 ns, the spatial - the order of 1 mm. Measuring the density dynamics of high-temperature plasma with a similar time resolution represents a significant challenge. Traditional approach (repletion-rate, burst-mode) [2] is not applicable under the experimental conditions on the GOL-3. Therefore double-pulse Thomson scattering system has been developed [3]. This paper presents the modification of Thomson scattering system for studying the density profile dynamics, which allows measurements at 8 points along plasma radius at two points in time. Two pulses from a neodymium laser λ = 1054 nm, with a time interval between t = 60-150 ns, the energy E = 10-20 J and a duration of τ = 20-40 ns, have been used for scattering in the plasma. In result from the experiments the data on a fast local dynamics of the plasma density in the various operation regimes have been obtained. The dynamics of the plasma density in some registration channels has reached 30% in during 100 ns. This work was supported by the Ministry of Education and Science, grant № 11.G34.31.0033 from Russian government for scientific research under the direction of leading scientists at Russian institutions of higher education on November 24, 2010. References [1]. Vyacheslavov L.N., Burmasov V.S., Kandaurov I.V., Kruglyakov E.P., Meshkov O.I., Popov S.S. and Sanin A.L. // Plasma physics and controlled fusion, 2002, Vol. 44, p. B279–B291. [2]. Van der Meiden H.J., Barth C.J., Oyevaar T., Varshney S.K., Donné A.J.H., Kantor M.Yu., Kouprienko D.V., Alexeev A., Biel W., and Pospieszczyk A. // Rev. Sci. Instrum., 2004, Vol. 75, p. 3849- 3851. [3]. Popov S.S., Vyacheslavov L.N., Ivantsivskiy M.V., Burdakov A.V., Kasatov A.A. and the GOL-3 team // Abstracts of 8th Intern. Conf. on Open Magnetic Systems for Plasma Confinement, Novosibirsk, Russia, 2010, p. 98.

Primary authors

A.A. Kasatov (Novosibirsk State University) Prof. Alexander Burdakov (Budker Institute of Nuclear Physics) L.N. Vyacheslavov (Budker Institute of Nuclear Physics) M.V. Ivantsivskiy (Budker Institute of Nuclear Physics) Dr Sergei Popov (Budker Institute of Nuclear Physics) Dr Sergey Polosatkin (BINP) V.V. Postupaev (Budker Institute of Nuclear Physics)

Presentation materials