Influence of Solar Wind Dynamic Pressure on Hiss Distribution Based on Van Allen Probe Observations

As a common plasma waves, whistler mode waves play a crucial role in the acceleration and scattering of energetic electrons in the magnetosphere. Numerous previous statistical studies have demonstrated that geomagnetic activities have a significant impact on the distribution of whistler waves. However, reports on the influence of solar wind activities on them are predominantly event-based. Five years of data from the Van Allen Probes were used for statistical analysis. After excluding the influence of substorm injections, the distribution of plasmaspheric hiss under different solar wind dynamic pressures were investigated. The results indicate that as the solar wind dynamic pressure intensifies, the amplitudes of hiss waves at 30～200 and 200～500 Hz exhibit a weakening trend and show a negative correlation with the change in solar wind dynamic pressure. In contrast to low frequency hiss, for hiss at 500～1000 Hz and 1000～2500 Hz, their amplitudes show a positive correlation trend with the change of solar wind. Additionally, there is no distinct peak in the distribution of hiss at magnetic latitudes, suggesting that most of the observed hiss is not locally excited. The different responses of hiss in different frequency bands to the solar wind dynamic pressure may be attributed to the fact that the source region is affected to varying degrees when the solar wind dynamic pressure increases. Studying the response of hiss to changes in the solar wind plays an important role in understanding the origin and evolution of hiss.