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Study of NBI-caused LH transition at low density in the TUMAN-3 M tokamak
| Content Provider | Semantic Scholar |
|---|---|
| Author | Askinazi, L. G. Chernyshev, Fedor V. Irzak, M. A. Komarov, A. D. Kornev, Vyacheslav A. Krikunov, S. V. Krupnik, L. I. Lebedev, Sergey V. Melnik, Anastasia D. Razumenko, D. V. Rozhdestvensky, V. V. Smirnov, Aleksandr I. Tukachinsky, Alexander Vildjunas, M. I. Zhubr, N. A. |
| Copyright Year | 2010 |
| Abstract | 98 . 0 74 . 0 73 . 0 20 042 . 0 S B n P T thr = , here: thr P in MW, 20 n – average density in 10 20 m, T B – toroidal magnetic field in T, S – area of the LCFS in m, factor 0.42 is derived for deuterium plasmas. This scaling describes well the required heating power behavior with density, toroidal magnetic field and plasma size, provided that plasma density exceeds some minimum value nmin . When plasma density is close or below nmin , Pthr increases dramatically, hampering the LH transition or even making it impossible [2,3,4,5]. Physical mechanisms underlying the above scaling, as well as increase in Pthr towards lower density, are not clear yet. Since Hmode is crucial for plasma performance in future thermonuclear reactor, i.e. ITER, it is essential to investigate processes responsible for H-mode power threshold. In the present paper an attempt is made to study physics behind the LH transition at low density. Generally accepted paradigm states that the LH transition is a result of turbulent transport suppression by sheared rotation caused by Er×B drift. Extensive experimental and theoretical investigation evidences to this point of view [6,7,8,9]. In the frame of this approach, plasma heating leads to Er generation, and when |dEr/dr| is strong enough, confinement bifurcation (LH transition) takes place. On the other hand, if radial electric field and/or plasma rotation is created by an external source, i.e. using edge plasma polarization by a biased electrode, LH transition is possible without increase in plasma heating, even at low density [6,9]. Figure 1 shows operational domain of the TUMAN-3M tokamak ( 0 R =0.53 m, |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://ocs.ciemat.es/EPS2010PAP/pdf/P1.1005.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
