Field-aligned and transverse plasma-potential structures induced by electron cyclotron waves

It is demonstrated that potential structures of a magnetized plasma column can be controlled by electron cyclotron waves of azimuthal mode number m=±1. A field-aligned plasma potential structure, i.e., an electric double layer with the potential jump corresponding to the ion flow energy is created around the electron cyclotron resonance point at the center and peripheral areas of the plasma column for m=+1 and -1 modes, respectively. As a result, transversely outward and inward electric fields are locally generated. Our experimental results show that the created potential structures are greatly relevant to the polarization profiles of the injected waves and the resultant heating profiles.