EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A Statistical Study of Foreshock Environment under Radial IMF Conditions

Gilbert Pi, Anna Salohub, Niki Xirogiannopoulou, Zdeněk Němeček, and Jana Šafránková
Gilbert Pi et al.
  • Charles University, Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Prague, Czechia (

The foreshock is a turbulent region in front of the quasi-parallel bow shock. The reflected particles from the bow shock and interaction with oncoming waves in the solar wind create it. The foreshock is usually located at the dawn side. However, the foreshock region is relocate to the nose of the bow shock and covers all the dayside magnetospheric system when IMF points to radial or anti-radial directions. This change creates many unusual phenomena in the magnetospheric system, such as the magnetopause expansion, and generates the foreshock transients, such as spontaneous Hot Flow Anomalies (sHFA). Previous studies revealed that foreshock transients are preferred to occur under a radial IMF condition, however, what is the reason for this preference is still unclear. Using THEMIS and MMS data, the analysis presents a statistical analysis to reveal the foreshock characteristics under the radial IMF to check the reasons for the preference of foreshock transients. The primary solar wind parameters in the foreshock and/or solar wind under these conditions are revealed. The ULF wave behavior is also taken account.

How to cite: Pi, G., Salohub, A., Xirogiannopoulou, N., Němeček, Z., and Šafránková, J.: A Statistical Study of Foreshock Environment under Radial IMF Conditions, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8347,, 2023.