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Triggered Ion-acoustic Waves in the Solar Wind
Author | Mozer, F.~S.; Vasko, I.~Y.; Verniero, J.~L.; |
Keywords | Solar Coronal Waves; Solar wind; 1995; 1534; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Parker Data Used |
Abstract | For more than 12 hr beginning on 2021 January 18, continuous narrowband electrostatic emissions were observed on the Parker Solar Probe near 20 solar radii. The observed <1000 Hz frequencies were well below the local ion-plasma frequency. Surprisingly, the emissions consisted of electrostatic wave packets with shock- like envelopes, appearing repetitively at a \raisebox-0.5ex\textasciitilde1.5 Hz rate. This repetitiveness correlated and was in phase with low-frequency electromagnetic fluctuations. The emissions were associated with simultaneously observed ion beams and conditions favorable for ion-acoustic wave excitation, i.e., Te/Ti \raisebox-0.5ex\textasciitilde 5. Based on this information and on their velocity estimates of about 100 km s$^-1$, these electrostatic emissions are interpreted as ion-acoustic waves. Their observation demonstrates a new regime of instability and evolution of oblique ion-acoustic waves that have not been reported previously in theory or experiment. |
Year of Publication | 2021 |
Journal | \apjl |
Volume | 919 |
Number of Pages | L2 |
Section | |
Date Published | sep |
ISBN | |
URL | |
DOI | 10.3847/2041-8213/ac2259 |