Yet another Bow Shock Study: Why Should you Care?

Jan Merka (L-3 Communications GSI)

During almost three decades of operation, the IMP-8 satellite collected 
an extensive amount of both plasma and magnetic field measurements. 
The entire dataset has been searched for all Earth's bow shock crossings 
observed by IMP-8 and more then 11,000 crossings were found. This large 
database has been employed to investigate bow shock properties under various
conditions. Accuracy of several bow shock models have been tested and 
lead to the conclusion that current bow shock models have difficulties 
predicting bow shock location for unusual conditions. Statistical and case
studies of bow shock observations revealed that the shock's position 
depends on the Earth's dipole tilt angle and the IMF orientation with respect 
to the solar wind flow. These two parameters have not been previously 
considered to have any influence on the bow shock's location.