Strong transport reduction in the helical core of the reversed-field pinch

• An explanation of the strong heating observed in the core of a reversed-field pinch in the quasi-single-helicity state is presented. A magnetic island is formed, in which the heat transport coefficient is much smaller than in the surrounding chaotic sea, because of the formation of well defined magnetic surfaces. The values of the thermal conductivity obtained with the M1TEV [F. Porcelli , Phys. Rev. Lett 82, 1458 (1999)] two-dimensional transport code are in very good agreement with the estimates of the ion diffusion coefficient inside the island, given by a Hamiltonian guiding center code. Moreover, the values of thermal conductivity are in the tokamak range, and are consistent with the peak temperatures measured in the Reversed Field eXperiment [P. Sonato , Fusion Eng. Des. 66-68, 161 (2003)] at Consorzio RFX, Padova, Italy. The effect of the island width and the different powers deposited inside the island on the final temperature peak are also investigated.

Subject headings

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Keyword

ELECTRON-TEMPERATURE MEASUREMENTS

HIGH TIME RESOLUTION

ACTIVE MHD CONTROL

SINGLE-HELICITY

SELF-ORGANIZATION

HIGH-BETA

RFX

CONFINEMENT

PARADIGM

STATES

Physics

Fysik

Publication and Content Type

ref (subject category)

art (subject category)