Casu Cinzia
UniCa About Professors and Researchers Cinzia Casu Research Research outcomes (IRIS)

Cinzia Casu

Magnetic configuration effects on the Wendelstein 7-X stellarator

B. Cannas;F. Pisano;
2018-01-01

Abstract

The two leading concepts for confining high-temperature fusion plasmas are the tokamak and the stellarator. Tokamaks are rotationally symmetric and use a large plasma current to achieve confinement, whereas stellarators are non-axisymmetric and employ three-dimensionally shaped magnetic field coils to twist the field and confine the plasma. As a result, the magnetic field of a stellarator needs to be carefully designed to minimize the collisional transport arising from poorly confined particle orbits, which would otherwise cause excessive power losses at high plasma temperatures. In addition, this type of transport leads to the appearance of a net toroidal plasma current, the so-called bootstrap current. Here, we analyse results from the first experimental campaign of the Wendelstein 7-X stellarator, showing that its magnetic-field design allows good control of bootstrap currents and collisional transport. The energy confinement time is among the best ever achieved in stellarators, both in absolute figures (τE> 100 ms) and relative to the stellarator confinement scaling. The bootstrap current responds as predicted to changes in the magnetic mirror ratio. These initial experiments confirm several theoretically predicted properties of Wendelstein 7-X plasmas, and already indicate consistency with optimization measures.
2018
Physics and Astronomy (all)
Files in This Item:
File Size Format  
57601_nphys-2017-08-02583-revision-clean.pdf

Solo gestori archivio

Type: versione pre-print
Size 2.17 MB
Format Adobe PDF
& nbsp; View / Open   Request a copy
2.17 MB Adobe PDF & nbsp; View / Open   Request a copy

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Questionnaire and social

Share on:
Impostazioni cookie