High density operation on the HT-7 superconducting tokamak

Citation
X. Gao et al., High density operation on the HT-7 superconducting tokamak, NUCL FUSION, 40(11), 2000, pp. 1875-1883
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
NUCLEAR FUSION
ISSN journal
0029-5515 → ACNP
Volume
40
Issue
11
Year of publication
2000
Pages
1875 - 1883
Database
ISI
SICI code
0029-5515(200011)40:11<1875:HDOOTH>2.0.ZU;2-B
Abstract
The structure of the operation region has been studied in the HT-7 supercon ducting tokamak, and progress on the extension of the HT-7 ohmic discharge operation region is reported. A density corresponding to 1.2 times the Gree nwald limit was achieved by RF boronization. The density limit appears to b e connected to the impurity contest and the edge parameters, so the best re sults are obtained with very clean plasmas and peaked electron density prof iles. The peaking factors of electron density profiles for different curren t and line averaged densities were observed. The density behaviour and the fuelling efficiency for gas puffing (20-30%), pellet injection (70-80%) and molecular beam injection (40-50%) were studied. The core crash sawteeth an d MHD behaviour, which were induced by an injected pellet, were observed an d the events correlated with the change of current profile and reversed mag netic shear. The MARFE phenomena on HT-7 are summarized. The best correlati on has been found between the total input ohmic power and the product of th e edge line averaged density and Z(eff) HT-7 could be easily operated in th e high density region MARFE-free using RF boronization.