# Presentation: 839305

## THE RADIO PLASMA IMAGER

**THE RADIO PLASMA IMAGER**

**BW Reinisch,**** ****DM Haines, IA Galkin, GC Cheney and GS Sales**
- University of Massachusetts Lowell
**JL Green, RF Benson, SF Fung, and  DL Gallagher**
- NASA Goddard SFC and Marshall SFC
**JL Bougeret and R Manning**
- Observatoire Paris-Meudon
**WWL Taylor and S Boardson**
- Raytheon STX, Goddard SFC
**PH Reiff**
- Rice University, Houston TX
**DL Carpenter**
- Stanford University

**Huntsville ‘98 Workshop**
**Session 4 - Imaging with Non-optical Techniques****	****	****28 October 1998**

## OUTLINE

- Radio Sounding
- The RPI Configuration
- Data Products
- http://image.gsfc.nasa.gov
- http://ulcar.uml.edu/rpi

## Orbital Characteristics

## Slide 4

## Simulated Plasmagram

## RPI Specifications

## RPI System Configuration

**(IV)  -X**

**+X (II)**

**+Y (III)**

**-Y (I)**

- +Y Axis Antenna
- Coupler and Antenna
- Deployer

- +X Axis Antenna
- Coupler and Antenna
- Deployer

- -Y Axis Antenna
- Coupler and Antenna
- Deployer

- -X Axis Antenna
- Coupler and Antenna
- Deployer

- RPI AXIAL ASSY

- Z Axis Antenna
- Preamplifier

- RPI Electronics

## RPI Waveforms

- short pulse (3.2 ms)
- long pulse (125ms)
- half-sec pulse
- 2-sec pulse
- n-chip complimentary phase codes,n=4,8,16
- chirp pulse (125 ms)
- staggered pulse sequence (768 chips)

## RPI Sounding Modes

- Echo Sounding w. Antenna Tuning
- Relaxation Sounding w/o Antenna Tuning
- Whistler Excitation (transmit f, receive diff.  f’s)
- Thermal Noise Passive Reception
- INSPIRE

## Radio Imaging

- Electric Field Ellipse

- E-Plane Normal =

**E** x **E’**

- EE’

- Echo Amplitude =

- E2  + E'2

- Polarization =

- Direction of E-Plane Normal

**E**

**E’**

**E’ **is phase quadrature sample of** E**

## Antenna ConfigurationTransmitted Wave

- Antenna ConfigurationTransmitted Wave

- B - magnetic field
- E - transmitted electric field
- k - wave direction

## Received Ray Direction

- Ei and Eq are quadrature vectors and the cross product gives the arriving signal direction

## Reflections As Seen by RPI

- satellite

- Reflection 1

- Reflection 2

## PolarizationAxial Ratio of Characteristic Waves

- PolarizationAxial Ratio of Characteristic Waves

- No collisions
- ψ  is the angle between **k** and **B**
- Axial ratio is the same for ionic and electronic waves
- Major axes are along and orthogonal  to the magnetic field direction

## Characteristic Wave PolarizationAxial Ratio

- Characteristic Wave PolarizationAxial Ratio

**30 kHz**

**100 kHz**

**300 kHz**

- fp = 25 kHz
- fH = 1.5 kHz

## Test Case Geometry

## Polarization Ellipse Model

**  ****Transmitted:  **

**   ****Received:    **

**Ú = 0.995**

- Antenna X projection

- Antenna Y projection

- Ionic polarization (LH)

- Electronic polarization (RH)

## Topside Sounding - 1971

**ISIS Topside Ionogram **
**showing Plasma Resonance Modes**

**f****N**** = O-mode Plasma Resonance**
**f****H**** = Gyro Resonance**
**f****T**** = Upper Hybrid Resonance**
**f****X**** = X-mode Plasma Resonance**
**f****Z**** = Z-mode Plasma Resonance**

**Plasma resonance frequencies provide In-situ Ne and Magnetic Field Intensity**
**Remote echoes provide vertical Ne profiles **

## RPI Echo-map

## Mapping of Reflection Points

## “Plasmagram”

- “Plasmagram”

- Color schemes:
- Directions
- Doppler shift

## Thumbnail Surveys