Speaker
Dr
Victor Bochkov
(Pulsed Technologies ltd.)
Description
The problem of plasma structure stabilization is highly relevant for systems of low- and high-temperature plasma, in particular fusion experiment, and in order to cope with the problem different special configurations of current and magnetic systems are developed and deployed. However, the available solutions require construction of complex magnetic fields and consume considerable amounts of energy. With respect to thyratrons, which operation is characterized by the presence of normally several high current plasma channels, this issue has not been yet studied thoroughly.
On the example of thyratrons TDI-type (pseudospark switches) contemplates a method of the arc discharge spatial stabilization.
TDI-type thyratrons (pseudospark switches) are widely used in pulsed power applications [1]. Normally they are operated in circuits with grounded grid and, in fact, represent an arc gap, the life of which is mostly determined by erosion of its electrodes [2]. However our experience shows that TDI-thyratrons, operated on the left branch of the Paschen curve, feature certain essentials in the motion of arc channels when switching charge transfer of more than 0.1 C per shot with peak currents exceeding 10 kA. Besides, the way how the switch is connected in the circuit and the external environment, affects greatly on the service life of the tube.
Based on experimental data, we analyzed the results of the influence of external conductive shield on stabilization of plasma channels in high-power pseudospark switches - thyratrons TDI-type. Both no-ferrous and ferrous shields have been tested. The preliminary calculation of the magnetic field distribution is presented. This research is a part of a work on improvement of switching capabilities of thyratrons used for transferring currents up to hundreds kA with switching energy more than 50 kJ.
Further increase of the life time is associated with as the stabilization of arc channels and with the requirement to the suppression of pinching in the central part of the electrode.
Similar processes take place not only in switches - thyratrons and spark gaps, but also in the high-current devices with the transportation of plasma at a sufficiently large distance (for example, in fusion colliders), so the construction of external thick screens therein may also contribute the stabilization of a plasma.
[1] Bochkov V.D., Korolev Y.D., Pulsed gas discharge switching devices // Encyclopedia of Low-Temperature Plasma, Ed. akad. V.E.Fortov. An introductory Book 4, Section № XI.6, Moscow, "Science", 2000, s.446-459.
[2] J.Slough, C. Pihl, V.D. Bochkov, D.V. Bochkov, P.V. Panov, I.N. Gnedin, «Prospective Pulsed Power Applications Of Pseudospark Switches», 17th IEEE International Pulsed Power Conference, 2009, Washington, DC, pp. 255-259.
Primary author
Dr
Victor Bochkov
(Pulsed Technologies ltd.)
Co-authors
Mr
Dmitriy Bochkov
(Pulsed Technologies ltd.)
Prof.
Sergey Krivosheev
(Peter the Great St.Petersburg Polytechnic University)
Dr
Yuri Adamian
(Peter the Great St.Petersburg Polytechnic University)
