The solar wind is a thin, hot gas given off by the sun. Charged particles in thi
ID: 2277128 • Letter: T
Question
The solar wind is a thin, hot gas given off by the sun. Charged particles in this gas enter the magnetic field of the earth and can experience a magnetic force. Suppose a charged particle traveling with a speed of 8.84E+6 m/s encounters the earth's magnetic field at an altitude where the field has a magnitude of 1.23E-7 T. Assuming that the particle's velocity is perpendicular to the magnetic field, calculate the radius of the circular path on which the particle would move if it were an electron.
Explanation / Answer
Answer: A three-spacecraft project to study the interaction between the solar wind and the Earth 's magnetosphere. Transfer to an interplanetary trajectory (and the name change) was performed via a 119-km-altitude, gravity-assist, lunar swingby on 22 December 1983. Navigation support during interplanetary cruise and comet en- counter was provided by orbit determination utilizing radio metric data from the DSN 64-meter antennas in Goldstone, California and Madrid, Spain. Orbit solutions yielding predictions of 50- km geocentric delivery accuracy in the target aim plane were achieved during interplanetary cruise and at comet encounter using 6-to-l 2-week data arcs between periodic attitude-change maneuvers. One-sigma two-way range and range rate residuals were consistently 40 meters and 0.2 mm/s or better, respectively. Non-gravitational forces affected the comet's motion during late August and early September 1985 and caused a 2300-km shift in the orbit of the comet relative to the spacecraft. This neces- sitated a final ICE orbit trim maneuver 3 days prior to encounter. Near-real-time assess- ment of two-way 2-GHz (S-bandj Doppler pseudo-residuals during the June and July 1985 trajectory change maneuvers aided in calibration of the spacecraft's thrusters in preparation for this final critical maneuver. Post-flight analysis indicates tail centerline passage was achieved within 10 seconds of the predicted time and geocentric position uncertainty at encounter was less than 40 km. I. Introduction particles and fields in the solar wind upstream of the Earth. a u* ?