Living With a Star Radiation Belt Storm Probes and Associated

Geospace Missions

D. G. Sibeck

Project ScientistNASA Goddard Space Flight Center

Geospace: Part of the Integrated LWS Plan

Distributed network of spacecraft providing continuous observations of Sun-Earth system Solar and Heliospheric Network observing the Sun & tracking disturbances from the Sun to Earth

Geospace Network uses a comprehensive set of spacecraft to diagnose the Geospace response

Stereo Lag

Stereo Lead

Solar Probe

• •Radiation Belt Storm Probes•Ionosphere-Thermosphere Storm Probes•UV Imager: O/N2 and Electron Density•SDO observations of EUV input

Original Geospace Mission Concept

The Radiation Belt Storm Probes Mission is in Phase A Formulation

Radiation Belt Storm Probes – twin spacecraft in highly elliptical orbits to understand the basic principals behind relativistic particle acceleration, transport, and loss.

Launch 2012Perigee: ~630 km altitudeApogee ~5.8 Re geocentric altitudeInclination ~10°Sun pointing, spin stabilizedDuration 2 years (expendables 4 years)

•Physics of the radiation belts are the physics of•Charge particle acceleration, transport, and loss.

Radiation Belts:Our Window on Fundamental Physics

• Source, loss, and transport processes

• Shock-associated creation and decay of radiation belts;

• Quantifying adiabatic and nonadiabatic processes;

• ”Seed" or source populations;

• Ring current and its effects on energetic particles;

• Data assimilation and specification models --> for practical applications

LWS Geospace RBSP Study Objectives

Mission Approach

•Simultaneous two-point measurements by

• identical spacecraft in common orbits.

•with a slow separation in phase,

•lapping one another 4-5 times/year,

•Covering the full range of local times in 2 years.

•Apogee of ~ 5.8 Re to sample outer belt and ring current.

•Perigee of ~ 630 km to sample inner belt.

•Simultaneous two-point measurements by

• identical spacecraft in common orbits.

•with a slow separation in phase,

•lapping one another 4-5 times/year,

•Covering the full range of local times in 2 years.

•Apogee of ~ 5.8 Re to sample outer belt and ring current.

•Perigee of ~ 630 km to sample inner belt.

plasmasphere

outer radiationbelt

1

23

Precession

Radial Profiles -->Distinguish Mechanisms

•When closely spaced-->

• determine radial phase space density gradients and discriminate between proposed source/loss regions and processes.

Convection

RadialDiffusion

LocalAcceleration

Spatial Extent

•When widely separated -->

•measure spatial extent of ring current asymmetries and wave fields.

Identify Source Populations

•Measure ‘seed’ or source populations: Plasma sheet Substorm injected plasma Pre-existing relativistic particles Solar Energetic Particles.

•and accelerated populations simultaneously.

4. Selected Investigations

• NASA/HQ selected the following experiments:– ECT (Spence, Boston U.) Energetic Particle Composition

and Thermal Plasma Suite– EMFISIS (Kletzing, U. Iowa) Electric and Magnetic Field

Instrument Suite and Integrated Science– EFW (Wygant, U. Minnesota) Electric Field and Waves

Instrument for the NASA RBSP Mission– RBSPICE (Lanzerotti, N.J. Inst. Technology) Radiation Belt

Storm Probes Ion Composition Experiment

• NASA entered into a partnership agreement with the NRO, who will supply:– RPS (Groves) Relativistic Proton Spectrometer

The Radiation Belt Storm Probes: Particle Experiments

The Radiation Belt Storm Probes: Field and Wave Experiments

Three Missions of Opportunity in Competitive Phase A Study

GOLD MOREBARREL

Robyn Millan Dartmouth College

Balloon Array for RBSP Relativistic Electron

Losses

Daniel Baker

U. Colorado Boulder

Mission of Opportunity RadBelt Experiment

Richard EastesU. Central Florida

Global-scale Observations of Limb

and Disk

–Final reports due September 12, 2007

–Result could augment RBSP and/or IT science.