Year: 2013
Type: article
Abstract: Rotation is favorable for confinement, but a stellarator can rotate at high speeds if and only if it is sufficiently close to quasisymmetry. This article investigates how close it needs to be. For a magnetic field B = B 0 + α B 1 , where B 0 is quasisymmetric, α B 1 is a deviation from quasisymmetry, and α ≪ 1, the stellarator can rotate at high velocities if α < 1/2 , with the ion Larmor radius over the characteristic variation length of B 0 . The cases in which this result may break down are discussed. If the stellarator is sufficiently quasisymmetric in the above sense, the rotation profile, and equivalently, the long-wavelength radial electric field, are not set neoclassically; instead, they can be affected by turbulent transport. Their computation requires the O ( 2 ) pieces of both the turbulent and the long-wavelength components of the distribution function. This article contains the first step towards a formulation to calculate the rotation profile by providing the equations determining the long-wavelength components of the O ( 2 ) pieces.
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: G3743495416, G7797568112
OpenAlex ID: W2079088771