Particle and field measurements of the Starfish diamagnetic cavity
Article first published online: 16 DEC 2006
Copyright 2006 by the American Geophysical Union.
Journal of Geophysical Research: Space Physics (1978–2012)
Volume 111, Issue A12, December 2006
How to Cite
2006), Particle and field measurements of the Starfish diamagnetic cavity, J. Geophys. Res., 111, A12211, doi:10.1029/2006JA011827.(
- Issue published online: 16 DEC 2006
- Article first published online: 16 DEC 2006
- Manuscript Accepted: 25 SEP 2006
- Manuscript Revised: 10 JUL 2006
- Manuscript Received: 2 MAY 2006
- diamagnetic cavity;
- radiation belt
 Recently analyzed beta particle and magnetic field measurements obtained from five instrumented rocket payloads located around the 1962 Starfish nuclear burst are used to describe the diamagnetic cavity produced in the geomagnetic field. Three of the payloads were located in the cavity during its expansion and collapse, one payload was below, and the fifth was above the fully expanded cavity. This multipoint data set shows that the cavity expanded into an elongated shape 1840 km along the magnetic field lines and 680 km vertically across in 1.2 s and required an unexpectedly long time of about 16 s to collapse. The beta flux contained inside the cavity was measured to be relatively uniform throughout and remained at 3 × 1011 beta/cm2 s for at least 7 s. The plasma continued to expand upward beyond the fully expanded cavity boundary and injected a flux measuring 2.5 × 1010 beta/cm2 s at H + 34 s into the most intense region of the artificial belt. Measured 10 hours later by the Injun I spacecraft, this flux was determined to be 1 × 109 beta/cm2 s.