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Van Allen Probes Ion Composition Experiment

RBSPICE will determine how space weather creates what is called the “storm-time ring current” around Earth and determine how that ring current supplies and supports the creation of radiation populations.

The geomagnetic field drives relativistic electron motion via time-dependent gradient-curvature drift. Thus, structural variations of the inner magnetospheric field due to storm-time ring current growth control transport and losses in the outer belt.

This investigation will accurately measure the ring current pressure distribution, which is needed to understand how the inner magnetosphere changes during geomagnetic storms and how that storm environment supplies and supports the acceleration and loss processes involved in creating and sustaining hazardous radiation particle populations.

RBSPICE Science Investigation Objectives:

  • Understand the effects of the ring current and other storm phenomena on radiation electrons and ions
  • Understand how and why the ring current and associated phenomena vary during storms
  • Support development and validation of specification models of the radiation belts for solar cycle time scales

Measurement Requirements: Hot plasma pressure must be derived to calculate the ring current contribution to storm-time magnetic fields. Thus, it is necessary to resolve the full energy spectrum of the ring current as well as its composition (H, He, O).

RBSPICE Instrument:

Image of RBSP-RBSPICE Instrument

Puck – ring-current ion composition, pitch-angle, and energy sensor
RBSPICE-Puck covers the full range of expected ring current intensities, from quiet to extreme events, with a factor of 10 margin against saturation.
Measurement quality is independent of the angle between the B-field and the spin axis.
- Ion composition energy range is low enough to determine the complete Ring Current energy density.
- High angle and energy resolution provide detailed pitch-angle and energy spectra: Δθ = 22.5°, ΔE/E = 0.1

More information about RBSPICE can be found at

Click to visit the NASA web site. Click to visit the APL web site.

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