The gross character of the geomagnetic field in the solar wind

Abstract

The effect of a rapidly moving highly conducting solar plasma, or solar wind, on the earth's magnetic field should be to deform it and confine it; it should not be to pull out to infinity magnetic lines of force which otherwise would lie close to the earth. At low latitudes the geomagnetic field is strengthened by the interaction at all distances from the earth out to the confining boundary, beyond which there is solar plasma and no geomagnetic field. At high latitudes, however, the geomagnetic field is weakened by the confining action of the solar wind. The shape that the deformed geomagnetic field should assume is roughly that of a tear drop; the marked lack of symmetry in the deformed field must be an important factor in space investigations such as measurements of trapped radiation or geomagnetic field. The boundary between the geomagnetic field and the solar plasma should be turbulent; there is a possibility that the presence of the hydromagnetic waves generated by the turbulence will open the tail of the tear drop, thus modifying the confinement of the field by the solar wind.