# Presentation: 153649

**Synoptic Studies of**
**Earth's Plasmasphere**
**with the IMAGE**
**Extreme Ultraviolet**
**Imager**

## Earth’s Plasmasphere

**Earth's plasmasphere is a torus of cold (~1 eV), dense (>10****3****/ cc) plasma that is populated by the outflow of ionospheric plasma along mid- and low-latitude magnetic field lines. **

**H****+**** is the principal plasmaspheric ion, but He****+**** accounts for ~20% of the plasmaspheric plasma. The plasma is trapped on magnetic field lines that rotate with Earth and thus "co-rotates" with them.**

**Earth’s Plasmasphere**

## g = ~1.1  10-4 sec-1

- The light detected by EUV comes from
*Resonant Scattering*
*of 30.4-nm sunlight*

- The scattering rate or “*g*-value”:

*g* = ~1.1 ****** **10-4 sec-1
-     for He+ at 1 AU

## The surface brightness is given by a line integral along the line of sight for each pixel:

- Surface Brightness of the Plasmasphere

## Measurement Requirements

**Measurement Requirements**

- Measure emissions of brightness <1 R in 10 minutes.
- Encompass the entire plasmasphere in the field of view.
- Provide spatial resolution of 0.1 RE from apogee (0.6).
- Accommodate bright ionospheric emissions.
- Reject contaminating emissions.
- (Operate from a spinning platform.)

## EUV Sensor Head and Detector

**EUV Sensor Head and Detector**

**Detector**
- Triple MCP + Wedge & Strip
- 40 mm diameter
- Spherical focal surface, R=70 mm

**Spherical Mirror**  f/0.8   R=135 mm
- Multilayer Coating for 30.4 nm

**Aluminum Entrance Filter**
- Transmits 30% at 30.4 nm
- Blocks H Ly-

## EUV Structure

**Three Identical Sensor Heads**

**Detector Electronics**

***Rear View***

**Cover cut away to show interior**

**Main Electronics Enclosure**

**High-Voltage Power Supply**

***Front View***

**EUV Structure**

## Imaging Using Time-Delayed Integration

**Imaging Using Time-Delayed Integration**

- 30° **** 360°

## Satellite Spin

- Instantaneous
- Field of View

- 2/3 of Sky in Full Field of View

**EUV Field of View on the Sky**

## Plasmasphere 

- Plasmasphere
- He+ 30.4 nm

## Plasmasphere Features

*Plasmasphere Features*

- Convection Tails
- Shoulders
- Symmetric Radial Features
- 	Voids, Fingers
*    **Other Regions*
- Aurora

## Convection Tails

- Carpenter, 1983

- Extend sunward from the dusk sector of the main body of the plasmasphere.
- Junction with main body corotates with magnetic field.
- Typical size scale: ~4 RE long, ~1 RE wide
- Ten instances of convection tails identified in the period 20 May to 31 August 2000.
- Each tail formed during or shortly after a period of Kp at least 5.

- 24 May 2000    09:13 UT

## Time Sequence from 24 May 2000

**Time Sequence from 24 May 2000**

## 24 May 2000

**24 May 2000**
**06:03 - 10:14**

## 24 May 2000  06:58

- 24 May 2000  09:58

## The “Cow-Lick”

**The “Cow-Lick”**

## 29 July 2000

**29 July 2000**
**01:35 - 09:56**

## 14 July 2000

- 06:02 – 10:48

- Tail, Multiple
- Structures

## 11 August 2000

- 17:04 – 22:30

## 2 Steps

- 10 July 2000
- 02:15 - 09:34

## 1 August 2000

- 15:27 - 20:03

## 29 Aug 2000

- 12:25 - 17:01

## Symmetric Radial Structures

*Voids and Fingers*
- Radially aligned, but differ in size in both radial and azimuthal directions.
- Distinct or part of a continuum?
- Voids
- 	Large size ( 1 x 2 RE)
- 	Long-lived (~ 40 hours)
- 	At least two instances recorded
- 		24 June, 1 July 2000

- 24 June 2000  17:02

- A Void

## 24-25 June

**24-25 June**
**2000**

## 13 July 2000

**13 July 2000**
**01:20 - 07:38**

## A Sampler

**A Sampler**

## More information and movies at

**Follow-Up**

- http://euv.lpl.arizona.edu/euv/