# Presentation: 513212

## The IMAGE Mission

**J. L. Green**
**Goddard Space Flight Center**
**Presentation at The Catholic University of America**
**December  1, 1999**

## Outline

**What is the Magnetosphere?**
**Geomagnetic Storms and Substorms**
**IMAGE Mission Science Objectives**
**Instrumentation - “Seeing the Invisible”**
**Expected Accomplishments**
**Summary**

**http://image.gsfc.nasa.gov/**

## Slide 3

## Slide 4

## Magnetospheric Currents - Quiet

## Slide 6

## Slide 7

## Magnetopause Dynamics

**Increase solar wind pressure or reconnection can change the position of the magnetopause by several Re**
- Large scale magnetosphere reconfiguration occurs
- First indication of a geomagnetic storm or substorm will occur
**Reconnected magnetic field lines allow solar wind plasma to enter into the magnetosphere**
**A boundary layer of plasma is found Earthward of the magnetopause**
**Questions that remain to be answered:**
- What is the mapping of magnetopause field lines back to the Earth?
- What is the origin and dynamics of the boundary layer?
- Where does solar wind plasma that enters in the magnetosphere go?
- Does reconnection occur as small scale or large scale phenomena?
- Do large scale surface waves form on the magnetopause and how do they propagate?

## Slide 9

## Magnetospheric Currents - Disturbed

## Ring Current

**Ring current is largely carried by ions in the 20-200 keV energy range**
**Ring current plasma is believed to come from both the solar wind and the ionosphere**
*Insitu* measurements have found O+ is larger than H+ in large storms
- O+ indicates ionospheric origin, H+ can be both ionospheric or solar wind
**Questions that remain to be answered**
- What is the origin of the ring current ions?
- What are the mechanisms for energization and transport into the ring current region (L=2-7 Re)?
- What are the mechanisms for the loss of the ring current during the storm recovery phase?

## Plasmasphere Dynamics

## Plasmasphere Dynamics

## Plasmasphere 

**Plasmasphere is made up of low energy plasma from the ionosphere **
**Plasmasphere varies in size from 5 to 2.5 Re depending on phase of the geomagnetic storm**
**Questions to be answered:**
- How is the plasmpause boundary established at a new location during a geomagnetic storm?
- What are the processes that refills or erodes the plasmasphere?
- How does the  global shape of the plasmasphere evolve during erosion and reformation?

## Magnetospheric Research

**Over the last 30 years magnetospheric missions use *****insitu***** measurements exclusively **
**Auroral imagers have been our only global view of magnetospheric dynamics**
- NASA missions: ISIS (1969), DE (1982), POLAR (1996)
**Mission science objectives have been narrowly defined to an understanding of specific plasma regions or dynamics**
**Until now there has been no mission to the “global magnetosphere”**
**Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) **
- All known imaging techniques are used
- Science objectives study global phenomena and look at the connections between individual plasma regions

## Orbital Characteristics

## IMAGE Instruments

**FUV Imagers**
- Geocorona (GEO) imager
- Spectrographic Imager (SI)
- Wideband Imaging Camera (WIC)
**EUV Imager**
- Extreme Ultra-Violet (EUV) imager
**Neutral Atom Imagers**
- High Energy Neutral Atom (HENA) imagers
- Medium Energy Neutral Atom (MENA) imagers
- Low Energy Neutral Atom (LENA) imagers
**Radio Sounder**
- Radio Plasma Imager (RPI)

## IMAGE Spacecraft

## Slide 20

## Wideband Imaging Camera (WIC)

**The Wideband Imaging Camera is designed to image the whole Earth and the auroral oval from above 4 Re **
** ****Spectral range is between 140 nm and 160 nm in the ultraviolet part of the auroral spectrum. **
**The WIC Characteristics are summarized below: **
- A curved image intensifier is optically coupled to a CCD and the optics provides a field of view of 17x17 degrees.
- Spectral range 140-160 nm
- Resolution elements of less than 0.1 degrees
- Temporal resolution 120 seconds
- 256 x 256 pixels (less than 100 km spatial resolution at apogee)
- Goal sensitivity 100 Rayleighs in final image

## Spectrographic Imager (SI)

**SI is designed to image the whole Earth proton aurora at greater than 4 Re. **
**Observes at the Doppler shifted Lyman H-alpha line at 121.82 nm in the ultraviolet part of the optical spectrum and rejects the non-Doppler shifted Lyman H-alpha from the geocorona at 121.567 nm. **
**The SI Characteristics are summarized below: **
- Doppler shifted spectral line at 121.82 nm
- Field of view 15x15 degrees
- Resolution elements of less than 0.15 degrees
- Temporal resolution 120 seconds
- 128 x 128 pixels (less than 100 km spatial resolution at apogee)
- Goal sensitivity 100 R in the presence of 10 kR at 121.6 nm

## Slide 23

## Geocorona (GEO) Imager

**GEO Observations**
- Far ultraviolet imaging of the Earth’s Geocorona
**Measurement Requirement**
- FOV: 1° x 360° for Geocorona
- Spatial Resolution: 90 km
- Spectral Resolution:Lyman alpha 121.6 nm
**Storm/substorm Observations**
- Image Time: 2 minutes generating 720 images/day
**Derived Quantities**
- Integrated line-of-sight density map of the Earth’s Geocorona
- Important input for ring current modeling in conjunction with the neutral atom imaging
- (Image at left from Rairden et al., 1986)

## Extreme Ultra-Violet (EUV) imager

**EUV Observations**
- 30.4 nm imaging of plasmasphere He+ column densities
**Measure Requirements**
- FOV: 90°x 90° (image plasmasphere from apogee)
- Spatial Resolution: 0.1 Earth radius from apogee
**Storm/substorm Observations**
- Image Time: 10 minutes generating 144 images/day
**Derived Quantities:**
- Plasmaspheric density structure and plasmaspheric processes

## Charge Exchange Process

## Generation of Neutral Atoms

## Simulation of Neutral Atom Imaging

## High Energy Neutral Atom (HENA)

**HENA Observations**
- Neutral atom composition and energy-resolved images over three energy ranges: 10-500 keV
**Measure Requirements**
- FOV: 90°x 120°
- Angular Resolution: 4°x 4°
- Energy Resolution (E/E):  0.8
- Sensitivity: Effective area 1 cm**2
**Storm/substorm Observations**
- Image Time: 2 minutes generating 720 images/day
**Derived Quantities:**
- Neutral atom image of composition and energy of the Ring Current and near-Earth Plasma Sheet
- HENA/MENA instrument data combined to make a provisional Dst index
- Plasma Sheet and Ring Current injection dynamics, structure, shape and local time extent

## Medium Energy Neutral Atom (MENA)

**MENA Observations**
- Neutral atom composition and energy-resolved images over three energy ranges: 1-30 keV
**Measure Requirements**
- FOV: 90°x 107°
- Angular Resolution:4°x 8°
- Energy Resolution (E/E):  0.8
- Sensitivity: Effective area 1 cm**2
**Storm/substorm Observations**
- Image Time: 2 minutes generating 720 images/day
**Derived Quantities:**
- Neutral atom image of composition and energy of the Ring Current and near-Earth Plasma Sheet
- HENA/MENA instrument data combined to make a provisional Dst index
- Plasma Sheet and Ring Current injection dynamics, structure, shape and local time extent

## Low Energy Neutral Atom (LENA)

**LENA Observations**
- Neutral atom composition and energy-resolved images over three energy ranges: 10-500 eV
**Measure Requirements**
- Angular Resolution: 8°x 8°
- Energy Resolution (E/E): 0.8
- Composition: distinguish H and O in ionospheric sources, interstellar neutrals and solar wind.
- Sensitivity: Effective area > 1 cm**2
**Storm/substorm Observations**
- Image Time: 2 minutes (resolve substorm development) generating 720 images/day
**Derived Quantities:**
- Neutral atom composition and energy of the Auroral/Cleft ion fountain
- Ionospheric outflow

**High Altitude**

**Low Altitude**

## Radio Plasma Imager

## Radio Plasma Imager (RPI)

## Principles of Radio Sounding

**Radio waves are reflected at wave cutoffs (n = 0)**
**In a cold, magnetized plasma**
- Ordinary (O-mode): Wave frequency =  *f**p*
- Extraordinary (X-mode): Wave frequency =
**Echo from reflections perpendicular to density contours**

**Echo**

**Refracted rays**

**Refracted rays**

- n=0

- n>0

- n<0

## Overview of Radio Plasma Imaging (RPI)

**RPI transmits coded EM waves and receives resulting echoes at 3 kHz to 3 MHz**
- Uses advanced digital processing techniques (pulse compression & spectral integration)
**RPI uses a tri-axial orthogonal antenna system**
- 500 meter tip-to-tip x and y axis dipole antennas
- 20 meters tip-to-tip z axis dipole antenna
- Transmitter can utilize either x or y or both x and y axis antennas
- Echo reception on all three axes
**Basic RPI measurements of an echo at a selected frequency **
- Amplitude
- Time delay (distance or range from target)
- Direction
- Wave polarization (ordinary or extra-ordinary)
- Doppler shift and frequency dispersion
***Insitu***** density and resonances measurements**

## Magnetospheric Density Structure

## Representative RPI Targets

**Magnetopause boundary layer****	****5 -20****	****20 - 40**
**Polar Cusp ****	****7 - 30****	****25 - 50**
**Magnetopause****	****10 - 60****	****30 - 70**
**Plasmapause****	****30 - 800****	****50 - 250**
**Plasmasphere****	****800 - 8x10****3****	****250 - 800**
**Ionosphere****	****8x10****3  ****- 1x10****5****	****800 - 3000**
**Optimal range to reflection point 1 to 5 R****E**** **
**RPI will detect these targets sufficiently often to define their structures and motions**

** ****	****Electron Density ****	****Plasma Freq.**
**Target****	****Range (cm****-3****)****	****Range (kHz)**

## Ray Tracing Calculations

**Ray Tracing Code**
- Developed by Shawhan [1967] & modified by Green [1976], has supported over 30 studies during the last 15 years
- Uses the Haselgrove [1955] formalism and cold plasma dispersion relations [Stix, 1992]
**Measured receiver noise level**
**Three-dimensional magnetospheric plasma model**
- Diffusive equilibrium plasmasphere [Angerami & Thomas, 1964]
- Plasmapause model [Aikyo & Ondoh, 1971]
- Magnetopause boundary [Roelof & Sibeck, 1993]
- With Gaussian or multi-Gaussian density profile
**Magnetopause density characteristic of MHD models**
- 4 times the solar wind density at subsolar point
- 1.1 times the solar density at the dawn-dusk meridian
- Solar Wind electron density = 10 /cc** **

## Slide 39

## Slide 40

## Radio Sounding

## Magnetopause Echoes and Density Structure

## Summary

**IMAGE is NASA’s first mission to the “global magnetosphere”**
**IMAGE uses all known remote sensing techniques for the magnetosphere **
**IMAGE will provide a unique view of how various magnetospheric phenomena are connected**
**IMAGE will provide potentially valuable space weather data**
**All IMAGE data is non-proprietary - open to everyone!**

## BACKUP

## Slide 45

## Spectrographic Imager (SI)

**SI Observations**
- Far ultraviolet imaging of the aurora
- Image full Earth from apogee
**Measurement Requirement**
- FOV: 15°x 15° for aurora (image full Earth from apogee),
- Spatial Resolution: 90 km
- Spectral Resolution (*top*): Reject 130.4 nm and select 135.6 nm electron aurora emissions.
- Spectral Resolution (*bottom*): 121.6 nm
**Storm/substorm Observations**
- Image Time: 2 minutes generating 720 images/day
**Derived Quantities**
- Structure and intensity of the electron aurora (top)
- Structure

## IMAGE Telemetry Modes

**Store and forward telemetry mode**
- On-board storage and high rate dump through DSN twice/day (13 hour orbit)
- SMOC receives Level-0 data and generates Level-1 (Browse Product)
- SMOC being developed at Goddard Space Flight Center
- Data products delivered to NSSDC for archiving and community distribution
**Real-Time mode**
- IMAGE broadcasts all telementry data in a real-time mode
- Data can be received by anyone
- Not routinely used by NASA
**Space Weather usage of IMAGE data by NOAA**
- Will receive real-time data from several tracking stations:
- Communications Research Lab (Tokyo), U.C. Berkeley and Naval Academy
- “Space Weather” products generated and used by NOAA at SEL, Boulder

## Potential IMAGE Space Weather Measurements

## IMAGE Team Members

**Principal investigator: Dr. James L. Burch, SwRI**
**U.S. Co-Investigators: **
- Prof. K. C. Hsieh & Dr. B. R. Sandel, University of Arizona
- Dr. J. L. Green & Dr. T. E. Moore, Goddard Space Flight Center
- Dr. S. A. Fuselier, Lockheed Palo Alto Research Laboratory
- Drs. S. B. Mende, University of California, Berkeley
- Dr. D. L. Gallagher, Marshall Space Flight Center
- Prof. D. C. Hamilton, University of Maryland
- Prof. B. W. Reinisch, University of Massachusetts, Lowell
- Dr. W. W. L. Taylor, Raytheon STX Corporation
- Prof. P. H. Reiff, Rice University
- Drs. D. T. Young, C. J. Pollack, Southwest Research Institute
- Dr. D. J. McComas, Los Alamos National Laboratory
- Dr. D. G. Mitchell, Applied Physic Labortory, JHU

## IMAGE Foreign Co-Is

**Foreign Co-Investigators**
- Dr. P. Wurz & Prof. P. Bochsler, University of Bern, Switzerland
-  Prof. J. S. Murphree, University of Calgary, Canada
-  Prof. T. Mukai, ISAS, Japan
- Dr. M. Grande, Rutherford Appleton Laboratory, U.K.
- Dr. C. Jamar, University of Liege, Belgium
- Dr. J.-L. Bougeret, Observatoire de Paris, Meudon
- Dr. H. Lauche, Max-Planck-Institut fur Aeronomie

## Other Team Members

**Participating Scientist: **
- Dr. G. R. Wilson, University of Alabama Huntsville
- Drs. A. L. Broadfoot & C. C. Curtis, University of Arizona
- Dr. J. D. Perez, Auburn University
- L. Cogger, University of Calgary, Canada
- Drs. R. F. Benson & S. F. Fung, Goddard Space Flight Center
- Drs. A. G. Ghielmetti, Y. T. Chiu, M. Schulz, & E. G. Shelley, Lockheed
- Dr. J. M. Quinn, University of New Hampshire
- Dr. J. Spann, Marshall Space Flight Center
- Prof. J.-C. Gerard, University of Liege, Belgium
- Dr. G. R. Gladstone, Southwest Research Institute
- Dr. D. L. Carpenter, Stanford University