Bow shock and magnetosheath waves at Mercury
Abstract
Mariner 10 measurements at the Mercury bow shock provide examples where the magnetic field is approximately parallel or perpendicular to the bow shock normal. Upstream of a broad irregular parallel shock, left hand circularly polarized waves are observed which cut off very sharply at approximately 4 Hz. Upstream of a perpendicular shock, right hand circularly polarized waves are observed which persist up to the Nyquist frequency of 12 Ha. Determination of the wave propagation vector as a function of frequency helps conclusively identify the waves as whistler mode waves propagating from the shock. The magnetosheath downstream of the parallel shock is disturbed more than that downstream of the perpendicular shock particularly below 1 Hz. In the latter case regular left hand polarized waves observed slightly above the proton gyrofrequency are identified as ion cyclotron waves with wavelength approximately 300 km which are Doppler shifted up to their observed frequency.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- July 1975
- Bibcode:
- 1975STIN...7532978F
- Keywords:
-
- Bow Waves;
- Magnetosheath;
- Mariner Space Probes;
- Mercury (Planet);
- Planetary Magnetospheres;
- Shock Waves;
- Magnetic Fields;
- Polarized Radiation;
- Wave Propagation;
- Astrophysics