Unanswered questions from CTX
The big question being addressed on CTX during the past year has been: Why was energy confinement not improved by increasing the mesh flux conserver radius from 40 cm to 67 cm. A comparison of decaying spheromaks with the same values of j and n in the two cases shows tau/sub B/2 improving roughly as R/sup 2/ but little change in T/sub e/. As a result, <..beta..>/sub vol/ has gone from approx. 7.0% to approx. 2.0% and the inferred energy confinement time has remained unchanged at approx. 23 ..mu..s. An energy balance analysis of the 40 cm case showed that the observed rapid particle loss could account for most of the energy loss while providing a mechanism for the removal of impurities. At 67 cm, tau/sub p/ has also improved by about a factor of 2, particle loss therefore contributes substantially less to energy balance and the achievement in CTX of j/n/sub e/ as high as 3 x 10/sup -14/ A.m (I/sub tor/ up to 1 MA), low-Z impurities should not be a problem. A question then arises: Is CTX faced with a new strong energy loss mechanism that is characteristic of spheromaks in general. This question is not simply answered because it may involve processes of thermal conduction or convection that cannot be directly measured. In the following paragraphs we discuss many of the topics that have been considered in this search.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 7231428
- Report Number(s):
- LA-UR-86-3875; CONF-861191-1; ON: DE87002903
- Resource Relation:
- Conference: Compact toroid workshop, Osaka, Japan, 21 Nov 1986; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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