A study of phase-steepened Alfven waves in a high-speed stream at 0.29 AU

This work performs a search of phase-steepened Alfven waves under a priori ideal conditions: a high-speed solar wind stream observed in one of the clo sest approaches to the Sun by any spacecraft (Helios 2). Five potential can didates were initially found following procedures established in earlier wo rk. The observed cases exhibited are-like or elliptical polarizations, and the rotational discontinuities that formed the abrupt wave edges were found at either the leading or the trailing part. The consideration of some addi tional specific parameters (mainly related to the relative orientation betw een mean magnetic field, wave and discontinuity) has been suggested here fo r an ultimate and proper identification of this kind of phenomenon. After t he inclusion of these calculations in our analysis, even fewer cases than t he five originals remain. It is suggested that optimum conditions for the d etection rather than just for the existence of these events have to be reco nsidered.