Solar wind interaction with the Earth's magnetic field: 3. On the Earth's bow shock structure

A classification of earth's bow shock structures on the basis of upstream MA, β, Δ = ∠ Bn (angle between shock normal and magnetic field direction) has been found. Typical properties for each case are studied. In particular, the downstream turbulence present in has been positively correlated with upstream β. It is suggested that the shock precursor, as far as low-frequency waves are concerned, is always due to waves generated upstream and carried by the solar wind. The use of the shock velocity allows estimation of the shock thickness: if MA > 3, the shock is a few ion gyroradii thick.