Rocket-borne vector measurement of the magnetic field associated with the mid-latitude Sq current system
Sandel, Bill Roy
Cloutier, Paul A.
Master of Science
A rocket-borne vector magnetometer has been used to infer the current magnitude, direction, and distribution in the mid-latitude Sq current system. The payload, comprising a scalar magnetometer with bias coil and a solar aspect sensor for determining vehicle attitude, was launched via a Nike-Apache sounding rocket from Wallops Island, Virginia at 7:05 local time (12:05 UT) on 7 August 1968. Complete vector information returned throughout the flight indicates that a southward equivalent surface current (vertically integrated current) of .15 amp/meter was encountered between the altitudes of 104 km and 118 km in both ascending and descending portions of the flight. Vertical distribution of the current within the layer was approximately uniform, and the layer was found to be horizontal within the accuracy of the experiment. It is suggested that the anomalously large current density and small vertical extent of the layer may be correlated with the existence of an intense and variable sporadic E layer detected in this altitude range by Wallops Island ionosondes. Because the exact form of the magnetometer signal is slightly dependent on vehicle dynamics, an analysis of this signal for the case in which the only motion of the rocket is simple spin has been expanded to include effects of vehicle coning and nutation, and it is shown that significant corrections for these motions are necessary in certain special cases.