Production of a stable high-temperature plasma in an adiabatic trap with a combined magnetic field
| Autor: | E.I. Kuznetsov |
|---|---|
| Rok vydání: | 1963 |
| Předmět: | |
| Zdroj: | Nuclear Fusion. 3:126-127 |
| ISSN: | 1741-4326 0029-5515 |
| DOI: | 10.1088/0029-5515/3/2/010 |
| Popis: | Several years ago Soviet scientists including Academician L. A. Artsimovich, B. B. Kadomtsev and M. S. Ioffe, suggested magnetic traps with fields of combined types in which the field strength increases in all directions from the region occupied by plasma, and does not vanish anywhere. Their purpose was to avoid simultaneously the flute instabilities that occur in mirror traps and the anticipated leakage from variation of magnetic moments at regions of zero field. As reported at the 1961 Salzburg conference (Nuclear Fusion, 1962 Supplement, Part 3, 1045), stabilizing windings added to a mirror trap increased the plasma lifetime from 100 to 500 mu sec and to a value that was assumed to be limited by the rate of ion charge exchange. Because of imperfect vacuum conditions in the device, this last conclusion could not be made with sufficient certainty. In 1962 a new device of the same kind, called PR-5,'' was made with more perfect vacuum conditions. It has a longitudinal field of 5 kOe, mirror ratio of 1.7, a stabilizing field at the wall of 4.5 kOe, 5 x 10/sup -8/ torr in the center with a steady hydrogen inlet to the plasma source, and a current half lifemore » of 55 msec in the stabilizing windings. A plasma density of 10/sup 9/ to 10/ sup 10/ cm/sup -3/ was obtained with an ion temperature of about 5 kev and an electron temperature of about 20 ev. The stabilizing windings are most effective. Lifetime increased to 3.5 msec at 1.5 x 10/sup -7/ torr (compared with 0.5 msec in the old device) and reached 15 to 30 msec at lower pressures. The Langmuir probe shows that deep plasma density pulsations disappear completely as the stabilizing field increases. The new data show that for beta about 10/sup -5/ the trap ensures stable confinement undisturbed by magnetohydrodynamic instabilities. (auth)« less |
| Databáze: | OpenAIRE |
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