Mona Kessel, NASA HQ Contributions by Jacob Bortnik, Seth Claudepierre, Nicola Fox, Shri Kanekal, Kris Kersten, Craig Kletzing, Lou Lanzerotti, Tony Lui, Barry Mauk, Joe Mazur, Robyn Millan, Geoff Reeves, David Sibeck, Sasha Ukhorskiy, John Wygant

Short description of RBSP Mission Instruments Outline Early Science Endeavors of RBSP EMFISIS EFW ECT RBSPICE RPS Coordinated Science BARREL THEMIS Theory & Modeling

Which Physical Processes Produce Radiation Belt Enhancement Events? What Are the Dominant Mechanisms for Relativistic Electron Loss? How do Ring Current and other geomagnetic processes affect Radiation Belt Behavior? The instruments on the two RBSP spacecraft will measure the properties of charged particles that comprise the Earth’s radiation belts and the plasma waves that interact with them, the large- scale electric fields that transport them, and the magnetic field that guides them. Provide understanding, ideally to the point of predictability, of how populations of relativistic electrons and penetrating ions in space form or change in response to variable inputs of energy from the Sun.

2 identically-instrumented spacecraft for space/time separation. Lapping rates (4-5 laps/year) for simultaneous observations over a range of s/c separations. 600 km perigee to 5.8 R E geocentric apogee for full radiation belts sampling. Orbital cadences faster than relevant magnetic storm time scales. 2-year mission for precession to all local time positions and interaction regions. Low inclination (10  ) to access all magnetically trapped particles Sunward spin axis for full particle pitch angle and dawn-dusk electric field sampling. Space weather broadcast Sun Space Weather & the White House

Radiation Belt Storm Probes InvestigationInstrumentsPI Energetic Particle Composition and Thermal Plasma Suite (ECT) Helium Oxygen Proton Electron Spectrometer (HOPE) Magnetic Electron Ion Spectrometer (MagEIS) Relativistic Electron Proton Telescope (REPT) H. Spence UNH Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) Low-Frequency Magnetometer (MAG) High-Frequency Magnetometer and Waveform Receiver (Waves) C. Kletzing University of Iowa Electric Field and Waves Instrument for the NASA RBSP Mission (EFW) J. Wygant University of Minnesota Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) L. Lanzerotti New Jersey Institute of Technology Proton Spectrometer Belt Research (PSBR) Relativistic Proton Spectrometer (RPS) D. Byers NRO

electrons protons 1eV1keV 1MeV 1GeV ion composition Energy Comprehensive Particle Measurements Radiation belts Ring current Plasmasphere

Comprehensive E and B Field Measurements DC Magnetic DC Electric AC Magnetic EMFISIS FGM EFW Perp 2D EMFISIS SCM 1kHz 1MHz AC Electric EFW Par 1D EFW E-fld Spectra Frequency 1mHz~DC 1Hz 10Hz Whistler mode EMIC BackgroundULF magnetosonic

1. What issues can be resolved about whistler mode interactions and their roles in electron energization and loss in the first 3 months? 2. What issues can be resolved about the large scale dynamics and structure with just the first few major geomagnetic storms? 3. What issues can be resolved about the source, structure, and dynamics of the inner (L<2) ion and electron belts in the first 3 months? RBSP First Science Endeavors

EMFISIS Science Understand correlations between various wave modes using varying separations between the two satellites. By start of normal operations (~60 days after launch) the satellites should be well separated. Contribution by Craig Kletzing Shprits et al., 2006 What wave modes happen at both satellites as a function of separation and location? What is the spatial coherence of chorus for small separation? What is the relationships between Chorus and hiss. Is chorus the parent wave for hiss? Are micro-bursts on SAMPEX and BARREL correlated to chorus or other wave modes? Does Chorus modulate with density changes? (ECT/HOPE) Question 1

Plasmaspheric Hiss 100Hz  few kHz Confined primarily to high density regions: plasmasphere, dayside drainage plumes. Generation mechanism not yet understood. Shprits et al., 2006 At high frequency (>1kHz) and low L source could be lightning At typical frequencies (few 100 Hz) source is likely magnetospheric

Plasmaspheric Hiss 100Hz  few kHz Why do we care? Confined primarily to high density regions: plasmasphere, dayside drainage plumes. Generation mechanism not yet understood. Shprits et al., 2006 At high frequency (>1kHz) and low L source could be lightning At typical frequencies ( few 100 Hz) source is likely magnetospheric Hiss depletes the slot region by pitch angle scattering.

Whistler mode Chorus 100Hz  5 kHz Why do we care? Shprits et al., 2006 Capable of emptying the outer belt in a day or less. Outside plasmasphere primarily on dawn side near equator. Generated by electron cyclotron instability near equator in association with injected plasmasheet electrons. Increased intensity during substorms and recovery. Associated with microburst precipitation. Major potential mechanism for electron acceleration.

EFW Science Explore the connection between large amplitude whistler waves and microburst precipitation. Contribution by John Wygant, Kris Kersten Question 1

Contribution by John Wygant, Kris Kersten Santolik, et al. (2003) - first report of large amplitude chorus elements Lower band chorus (<0.5fce) wave electric fields approaching 30mV/m Large Amplitude Whistler Brief (<1s) increases in the flux of precipitating MeV electrons, first satellite observations by Imhof, et al. (1992). Usually observed near dawn, but may extend from near midnight past dawn. Most commonly observed from L~4–6.

EFW Science Explore the connection between large amplitude whistler waves and microburst precipitation. Contribution by John Wygant, Kris Kersten Large Amplitude Whistler Occurrence Lorentzen et al., 2001 Microburst precipitation occurrence Statistically the connection is strong. Cully et al., 2008 Question 1

ECT Science Why do the radiation belts respond so differently to different storms? Contribution by Geoff Reeves Some geomagnetic storms can: (a) Cause dramatic radiation belt enhancement; (b) Deplete radiation belt fluxes; (c) Cause no substantial effect of flux distributions; (a) (b) (c) [Reeves et al., 2003] Question 2

ECT Science Identify the processes responsible for the precipitation and loss of relativistic and near relativistic particles, determine when and where these processes occur, and determine their relative significance. Contribution by Geoff Reeves Expected Electron Distributions Quick Science Study: Comparison of theory and observations for characteristic signatures of EMIC waves Compare PSD as a function of E and PA during a dropout. Do observations show expected signatures? 2D Energy-pitch angle diffusion model at fixed L Li et al., 2007 Question 2

RBSPICE Science If we have some geomagnetic storms during the first few months of RBSP operation, then we can address the following question. How is current density from protons, helium ions, and oxygen ions compared during weak and strong geomagnetic storms? H+H+ O+O+ Energy density of oxygen ions can dominate that of protons during intense geomagnetic storms Contribution by Tony Lui Hamilton et al., 1988 Question 2

RPS Science Discovery: What is the energy spectrum of the inner belt protons? Contribution by Joe Mazur Example of the wide variation in modeled inner belt spectra Few satellites have spent significant time near the magnetic equator and at the peak intensities of the inner belt. AP8 MIN: Sayer & Vette 1976; AD2005: Selesnick, Looper, & Mewaldt 2007 Ion energy spectrum is known to extend beyond 1 GeV, but the spectral details are not well established: shape, maximum energy, time dependence Electron spectrum unknown. How do electrons get to the inner belt? The dominant source for protons above ~50 MeV in the inner belt is the decay of albedo neutrons from galactic cosmic ray protons that collide with nuclei in the atmosphere and ionosphere (Cosmic Ray Albedo Neutron Decay, or CRAND). Question 3

BARREL Mission Contribution by Robyn Millan The proposed investigation will address the RBSP goal of, "differentiating among competing processes affecting precipitation and loss of radiation particles" by directly measuring precipitation during the RBSP mission. Launch 20 balloons each in January 2013 and January 2014 from Antarctica. BARREL will simultaneously measure precipitation over 8-10 hours of magnetic local time. Combine the measurements of precipitation with the RBSP spacecraft measurements of waves and energetic particles.

BARREL/RBSP Coordinated Science What is the loss rate due to precipitation versus magnetopause losses? RBSP: measure changes in in- situ trapped electron intensity BARREL: quantify precipitation at range of local times THEMIS: magnetopause losses Contribution by Robyn Millan Motivation: Recent results of Turner et al., 2012 (magnetopause shadowing) vs earlier results from e.g., Selesnick 2006, O’Brien 2004 (precipitation). Figure courtesy of A. Ukhorskiy RBSP THEMIS Measurements Question 1

THEMIS/RBSP Coordinated Science Contribution by David Sibeck First Planned Science Campaign Science Objectives: THEMIS has hours separation of the 3 satellites along the orbit. What are the cause(s) of dawn- dusk differences in ion fluxes during geomagnetic storms? What role does the Kelvin- Helmholtz instability play in particle energization, transport, and loss? What are the relative roles of EMIC waves in the dusk magnetosphere, chorus waves in the dawn magnetosphere, and hiss deep within the magnetosphere? Question 2

Coincident observation of chorus and hiss on THEMIS 1 inside plasmasphere, 1 outside plasmasphere Plasma wave instruments, recording simultaneously High resolution, correct frequency range Correct spatial regions, day side, ~equator Geomagnetic activity October 4 th, 2008 Contribution by Jacob Bortnik Question 1 Theory & Simulation/RBSP Coordinated Science

Chorus - Hiss Bortnik et al. [2009] Contribution by Jacob Bortnik Wave burst mode, 64-bin FFT, 20 Hz-4 kHz, every 1s  THEMIS-E: discrete chorus, 600 Hz- 3 kHz, f/f ce,   Average spectral time- series, 1.2 – 1.6 kHz, high correlation!  THEMIS-D: incoherent hiss, <2 kHz

Numerical Ray tracing  Ray trace all rays in allowable wave normal angles,    ~ -50 to -45, L=6 waves reflect toward lower L and propagate into plasmasphere  Timescale  :  1 s, enter plasmasphere,  2 s, 1 st EQ crossing  3.2 s, magnetospheric reflection  7.7 s, second EQ crossing  20 s completely damped Bortnik et al. [2008] Contribution by Jacob Bortnik

Theory & Simulation/RBSP Coordinated Science Question 2 ECT: measure changes in in-situ trapped electron intensity EMFISIS: measure magnetic field (FFT to generate ULF wave power) Measurements Global MHD (LFM) : simulate magnetospheric ULF waves driven by dynamic pressure fluctuations Simulation Radial Diffusion : transport elecrons across drift shells Theory & Modeling Contributions by Seth Claudepierre & Sasha Ukhorskiy Effect of ULF waves on radiation belt electrons

Pressure fluctuations In High Speed Stream excite magnetosphere (Pc 5 frequency range) Contribution by Mona Kessel Kessel, 2007

SW Contribution by Seth Claudepierre Solar wind dynamic pressure fluctuations can drive compressional ULF waves on the dayside LFM Simulation Driving frequency 10 mHz Claudepierre, 2010 that can excite toroidal mode FLRs. Eigenfrequency Profiles

Non-diffusive Transport Radial transport across the outer belt can be driven by a variety of ULF waves induced by SW and ring current instabilities. Transport exhibits large deviations from radial diffusion, which may account for the observed nonlinear response of electron fluxes to geomagnetic activity: even similar storms can produce vastly different radiation levels across the belt. Ukhorskiy 2009 Contribution by Sasha Ukhorskiy Solar Wind driven ULF waves lead to non-diffusive transport Radial transport in MHD field model dominated by drift resonant interactions, each producing large coherent displacement of the distribution.

RBSP launch Aug 23, 2012 RBSP team and the science community ready to get the data and *change* the theories.