Interaction of pellets with hot plasmas
The primary goal of the pellet injection into magnetically confined plasmas is the fuelling of the discharge. The pellets used are hydrogen or deuterium ice pieces with a volume of a few cubic millimetres. Fuelling by pellet injection is complementary to the conventionally used gas injection fuelling. The fuelling allows the stationary regulation of a discharge density if the device has a balanced particle sink. The injection of pellets into a plasma leads to an enormous heat transfer from the plasma to the pellet. For normal heat fluxes, the heat deposition to a solid surface and the heat propagation into the solid is described by the heat equation. If the incoming heat flux is so high that the surface material is evaporated before the heat sufficiently penetrates into the bulk, a new effect, called gas shielding, is observed. The calefaction leads to the formation of a vapour cloud at the contact point, which lifts the droplet from the hotplate and inhibits the heat transition by several orders of magnitude.
Bibliographic Reference: Report: JÜL-2980 EN (1994) 66 pp.
Availability: Available from Zentralbibliothek der Forschungszentrum Jülich GmbH, Postfach 1913, 5170 Jülich (DE)
Record Number: 199510164 / Last updated on: 1995-02-07
Original language: en
Available languages: en