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P olar E xperiment N etwork for G eospace U pper-atmosphere In vestigations Advancing the Vision for Global Studies. PENGUIn meets THEMIS.

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slide1

Polar Experiment Network for Geospace Upper-atmosphere Investigations

Advancing the Vision for Global Studies

PENGUIn meets THEMIS

PENGUIn team: Marc Lessard (UNH), Allan Weatherwax (Siena), Robert Clauer (VT), Mark J Engebretson (Augsburg), Harald Frey (UCB), Umran Inan (Stanford), James LaBelle (Dartmouth), Lou Lanzerotti (NJIT), Stephen Mende (UCB), Noel Petit (Augsburg), Slava Pilipenko (Augsburg), Aaron Ridley (UMich), Ted Rosenberg (UMD), Maria Spasojevic (Stanford).

THEMIS: Vassilis Angelopolous (UCLA), PI.

Or, an encounter between the goddess of wisdom and good counsel and … happy feet

slide2

PENGUIn Science

  • The PENGUIn research and analysis program employs Antarctica as an integrated Geospace Observatory to study particular aspects of the following broad topics
      • Polar cap and cusp physics
      • Substorm phenomena (emphasis on understanding signatures)
      • Radiation belt dynamics
  • PENGUIn research also incorporates numerical efforts to support
      • An operational space weather program with cooperation from NOAA and the U. S. Air Force
      • A PENGUIn-driven SWMF modeling effort to 1) specify the state of the high-latitude ionosphere in the southern, as well as the northern hemispheres, and 2) simulate magnetosphere-ionosphere coupling using first-principle models to address a wide range of topics, including to support GITM.
slide4

THEMIS in Fast Survey

Current effort:

High-latitude aspects of substorms and substorm signatures

Example on Mar-23, 2007:

Two substorm onsets (courtesy V. Angelopolous)

slide5

Ground-based observation at the South Pole - note VLF and ULF

Initial onset at near 1120, peak near 1450. Note earlier magnetic signatures at Pole in fluxgate and induction coils (high latitude). AE shows no activity before 1030.

slide6

THEMIS locations for Mar-23, 2007

http://sscweb.gsfc.nasa.gov/tipsod

THEMIS

POLAR

slide7

Mag

N(i,e)

V

Themis A data, showing onset at ~11:20 UT, including energetic particle injections (ref Liu et al.)

T

Ions

Elec

slide8

VLF detection of energetic particle injections at high latitudes? G. Abel (BAS) related VLF waves to injections at lower latitudes (Halley Station).

Data from South Pole (M. Spasojevic), showing onset signature - low frequency chorus, perhaps related to particle injections.

slide9

VLF detection of energetic particle injections at high latitudes? G. Abel (BAS) related VLF waves to injections at lower latitudes (Halley Station).

Excellent observations from P2 (-70 MLAT) of onset.

Significance:

1. Changes in ionospheric conductivity at onset previously thought to be due only to auroral brightening (electrons accelerated locally).

2. VLF and riometer data imply that particle injections also play a role. PENGUIn observations at high-latitude provide unique data, especially when combined with THEMIS.

slide10

Pi1B pulsations and substorms:

Irregular magnetic pulsations in the ULF frequency range 0.025-1 Hz and appearing as broadband bursts (Heacock, 1967)

We know that:

Pi1B pulsations are observed on the ground and are related to substorm onsets. They are localized to 21-02 MLT.

They have been detected by GOES (compressional) and FAST (sear mode) at substorm onsets (Arnoldy, 1998; Lessard, 2006), so can we see them at Cluster?

C. Mouikis has shown that:

- They are also observed at CLUSTER altitude (~19 Re)

- They are related to fast flows

- They are related to substorm onsets

- They are compressional waves at ~9 – 19 Re

slide15

Mar-23, 2007: Observations from Poker Flat

Observations of fast flows by THEMIS for this event not expected because of its location. However, we do expect excellent supporting data from GOES.

Longer term goal is to understand generation of fast flows, why they produce a Pi1B signature and how they couple energy to the ionosphere - PENGUIn/THEMIS conjunctions will be ideal for this.

slide16

LANL-LOE

LANL-LOP

Drift Westward

Drift Eastward

Duskside

LANL-97A

Midnight

1989-046

Dawnside

LANL data show the signatures excepted from the injection model.

first electron injection

at 11:21:00

first ion injection

at 11:19:50

slide17

Injections mainly in higher energy channels.

(>100 keV)

Injections in all energy channels

(30~100s keV)

slide18

These three satellite detected the signature of first injection in a good time sequence.

Particles were injected between LANL-97A and 1989-046.

No dipolarization was seen by THC.

11:18

THC SST ION

~1min

LANL-97A Ion

dipolarization-like fluctuation

1989-046

1989-046 Electron

~4min

LANL-97A

?

THEMIS-C

THEMIS-D A B

THD SST ION

2~3min

THEMIS A,B and D seen the injections associated with clear dipolarization signature.

slide19

03/23/2007 11:28

Goes 11

1989-046

Geotail

LANL-97A

THEMIS

POLAR

Cluster

slide20
Survey of CLUSTER data shows that Pi1B pulsations are consistently associated with substorm onsets and fast flows
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