Interplanetary observations of solar g-mode oscillations?

Abstract

By applying spectral techniques to magnetic field and plasma data from Helios 1 and 2, Pioneer 1 and 2, and Voyager 1 and 2 missions, an attempt has been made to find evidence for solar g-mode oscillations in the solar wind. It is demonstrated that analysis employing simple spectral techniques is unlikely to detect such oscillations. Using the multi-taper method, however, many 'significant' lines are identified. Unfortunately, we cannot conclude that such lines are necessarily the signature of solar g-mode oscillations because (i) these lines do not appear to be stationary; (ii) there is no evidence for the predicted signatures of asymptotic g-rhodes; and (iii) the statistics of these lines do not deviate significantly from pseudo-randomly generated data. We suggest that the difference between our conclusions and previous studies lies in the criteria used to identify these lines. Copyright 1996 by the American Geophysical Union.