Spectroscopic study of anomalous electric fields in peripheral regions of a current sheet plasma

We observed an unusual/anomalous asymmetry of the HeI 667.8 nm spectral line profiles emitted from the peripheral regions of a current sheet plasma, which is characterized by high electron density gradients. This asymmetry can be explained only by assuming that, in the plane perpendicular to the current in the sheet, there is a strong low-frequency oscillatory electric field, which considerably exceeds the ion electric microfield. Our calculations show that this field seems to correspond to either a circularly or nearly-circularly polarized wave in the current sheet plasma