Penguin meets themis
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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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PENGUIn meets THEMIS

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Penguin meets themis

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


Penguin meets themis

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.


  • Penguin meets themis

    PENGUIn station locations


    Penguin meets themis

    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)


    Penguin meets themis

    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.


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    THEMIS locations for Mar-23, 2007

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

    THEMIS

    POLAR


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    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


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    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.


    Penguin meets themis

    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.


    Penguin meets themis

    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


    Example september 20 th 2003 ground observations of pi1bs at substorm onset

    Example: September 20th, 2003 – Ground observations of Pi1Bs at substorm onset


    Penguin meets themis

    September 20th, 2003 – CLUSTER observations of Pi1Bs at substorm onset


    Penguin meets themis

    September 20th, 2003 – Polar observations of Pi1Bs at substorm onset


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    Can we relate Pi1B to flows observed by THEMIS to learn more?

    Mar-23, 2007: THEMIS event


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    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.


    Penguin meets themis

    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


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    Injections mainly in higher energy channels.

    (>100 keV)

    Injections in all energy channels

    (30~100s keV)


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    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.


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    03/23/2007 11:28

    Goes 11

    1989-046

    Geotail

    LANL-97A

    THEMIS

    POLAR

    Cluster


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


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