# Presentation: 199051

## Observations in the Lunar Orbit Environment

- Christina O. Lee & Janet G. Luhmann
- October 18, 2005

## “What do we know?”

## Lunar orbit environment, ecliptic plane point of view

## Geotail observations are main source of data for studying energetic particles inside magnetotail

- Adapted from Christon et al., *JGR*,* 10*3*, *23521, 1998.

- Geotail trajectory from October ‘92 to October ‘94

## At 60 Re, majority of sampling occurred in the magnetosheath region (Oct., ’92-’94)

| Plasma Regime | Occurrence frequency 
at 60 Re | Occurrence frequency
% |
| --- | --- | --- |
| Plasma Sheet | 1100 | 26 |
| Lobe | 80 | 2 |
| Boundary Layer | 400 | 10 |
| Magnetosheath | 2000 | 48 |
| Solar wind | 600 | 14 |

- Adapted from Christon et al., *JGR*,* 10*3*, *23521, 1998.

## Geotail EPIC (Energetic Particle and Ion Composition) instrument sampled energetic particles in the energy range that is low according to NOAA standards for solar proton events (10+ MeV)

- There needs to be more sampling in the lunar orbit at higher energy ranges.
- (Lunar Prospector detected energetic particles as background.)

## Multipoint observations are available for understanding SEPS at the lunar orbit

- Image credit: (left) http://pwg.gsfc.nasa.gov, (right) NASA Space Physics Data Facility

**Notes:**
Label “Lunar Prospector” on figure once I get it from Jasper for the September 30, 1998 event
Plot full Lunar orbit in orbit-plot?

## Observations with Lunar Prospector data

- Image credit: (left) http://pwg.gsfc.nasa.gov; J. Halekas (SSL/UCB),  (right) NASA Space Physics Data Facility

- Observations with Lunar Prospector data

**Notes:**
Label “Lunar Prospector” on figure once I get it from Jasper for the September 30, 1998 event
Plot full Lunar orbit in orbit-plot?

## Associated interplanetary data

- B-field magnitude

- Bz field

- Solar wind bulk velocity

- Image credit: (top left) http://pwg.gsfc.nasa.gov; (bottom left & right) NASA Space Physics Data Facility\

**Notes:**
Label “Lunar Prospector” on figure once I get it from Jasper for the September 30, 1998 event
Plot full Lunar orbit in orbit-plot?

## Image credit: (left) http://pwg.gsfc.nasa.gov,  (right) NASA Space Physics Data Facility

| Flare Max.
Day/UT | Flare magnitude | Location |
| --- | --- | --- |
| Sep 23/0713 | M7 | N18E09 |
| Sep 30/1350 | M2 | N23W81 |

| Particle Event Max.
Day/UT | Assoc. CME | CME type | CME speed |
| --- | --- | --- | --- |
| Sep 25/0130 | SOHO Mission Interruption |  |  |
| Oct 01/0025 |  |  |  |

**Notes:**
Label “Lunar Prospector” on figure once I get it from Jasper for the September 30, 1998 event
Plot full Lunar orbit in orbit-plot?

## Clementine CPT (Charge Particle Telescope) data also available, but limited

- Image credit: D. Baker, *Adv. Space Res., 19*, 1587, 1997.

## “What we don’t know and need to know for VSE?”

## What’s the significance of SEPs in the magnetotail?... there are ongoing efforts to model energetic particle access into the terrestrial magnetosphere ...

- Image credit: (left) Lyon et. al, *JASTP*, *66*, Issue 15-16, 1333-1350, 2004
-                       (right) Richard et al., *JGR, 107*, 2002

- CISM (_C_enter for _I_ntegrated _S_pace Weather _M_odeling) global MHD magnetosphere-ionosphere code

- MHD simulation by        R. Richard et al. (UCLA)

## “How do we get there?”

## Geotail observations are the main source of energetic particle data in the lunar environment – analyze!
Lunar Prospector provide data as background count rates
Need to restore Clementine data set

Need more sampling at higher energy ranges (10+ MeV)
Clementine data is limited 

Meanwhile: ongoing efforts to model and understand SEP access into magnetosphere (CISM, UCLA group)

- Lunar Prospector provide data as background count rates
- Need to restore Clementine data set
- Need more sampling at higher energy ranges (10+ MeV)
- Clementine data is limited
- Meanwhile: ongoing efforts to model and understand SEP access into magnetosphere (CISM, UCLA group)

## Another event: Moon upstream, Geotail in tail at 10 Re

- Image credit: (left) http://pwg.gsfc.nasa.gov, (right) NASA Space Physics Data Facility

## Observations with 

- Lunar Prospector data

- Image credit: (left) http://pwg.gsfc.nasa.gov; J. Halekas (SSL/UCB),  (right) NASA Space Physics Data Facility

## Associated interplanetary data

- Image credit: (top left) http://pwg.gsfc.nasa.gov; (right) NASA Space Physics Data Facility

## Image credit: (left) http://pwg.gsfc.nasa.gov; J. Halekas (SSL/UCB),  (right) NASA Space Physics Data Facility

| Particle Event Max.
Day/UT | Assoc. CME | CME type | CME speed |
| --- | --- | --- | --- |
| Aug 26/1055 | SOHO Mission Interruption |  |  |

| Flare Max.
Day/UT | Flare magnitude | Location |
| --- | --- | --- |
| Aug 24/2212 | X1 | N30E07 |

## Multi-point observations at other planetary locations are available and can provide larger-scale understanding of SEPs in the inner heliosphere

- (4-51 MeV)

- (4-51 MeV)

- Additional SEP measurements from the STEREO mission will become available in the near future (launch data May 2006!)

**Notes:**
How many times does IMP-8 go around Earth in a given day? How about Helios 1?

Discuss the different panels shown here – this is what we can obtain from space!!  

Interplanetary shocks are identified by characteristic changes in the plasma and field parameters (p. 144 Kallenrode):
Increase in plasma density, speed, and temperature
Jump in magnetic field strength

Expansion of the shock leads to decrease in the plasma and magnetic flux densities (and thus energy densities)

LASCO coronagraph on SOHO has a field of view from 1.1 solar radii to about 30 solar radii