ISSN:
1562-6938
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract In T-10 experiments, attempts were made to significantly exceed the Greenwald limit $$\bar n_{Gr} $$ during high-power (P ab=750 kW) electron-cyclotron resonance heating (ECRH) and gas puffing. Formally, the density limit $$(\bar n_e )_{\lim } $$ exceeding the Greenwald limit $$({{(\bar n_e )_{\lim } } \mathord{\left/ {\vphantom {{(\bar n_e )_{\lim } } {\bar n_{Gr} }}} \right. \kern-\nulldelimiterspace} {\bar n_{Gr} }} = 1.8)$$ was achieved for q L=8.2. However, as q L decreased, the ratio $${{(\bar n_e )_{\lim } } \mathord{\left/ {\vphantom {{(\bar n_e )_{\lim } } {\bar n_{Gr} }}} \right. \kern-\nulldelimiterspace} {\bar n_{Gr} }}$$ also decreased, approaching unity at q L≈3. It was suggested that the “current radius” (i.e., the radius of the magnetic surface enclosing the bulk of the plasma current I p), rather than the limiter radius, was the parameter governing the value of $$(\bar n_e )_{\lim } $$ . In the ECRH experiments, no substantial degradation of plasma confinement was observed up to $$\bar n_e \sim 0.9(\bar n_e )_{\lim } $$ regardless of the ratio $${{(\bar n_e )_{\lim } } \mathord{\left/ {\vphantom {{(\bar n_e )_{\lim } } {\bar n_{Gr} }}} \right. \kern-\nulldelimiterspace} {\bar n_{Gr} }}$$ . In different scenarios of the density growth up to $$(\bar n_e )_{\lim } $$ , two types of disruptions related to the density limit were observed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1134/1.1331134
Permalink