On the induced azimuthal electric field in the current drive of an odd-parity rotating magnetic field Available to Purchase

The azimuthal electric field $Eθω$⁠, which is induced by the axial oscillating magnetic field $Bzω$ of the odd-parity Rotating Magnetic Field (RMF) scheme, is experimentally found to play an important role in driving the toroidal plasma current. In the odd-parity RMF scheme, $Eθω$ at the middle plane of the field reversed configuration can generate the so-called punctuated betatron-orbital electrons to drive the toroidal current in addition to the current driven by the transverse component of RMF $Brω$⁠, whereas $Brω$ is the only driving mechanism in the even-parity scheme. In this work, $Eθω$ (or $Bzω$⁠) and $Brω$ are each studied to account for different current driving mechanisms. We report that $Eθω$ accounts for the more efficient current driving in our experiments.