A High-Latitude Window to Geospace Dynamics: PENGUIn

Pilipenko V.A.

PENGUIn and other national Antarctic arrays

Flux-gate magnetometers Search-coil magnetometers

>30 countries

+ auroral imagers, riometers, VLF antennas, …

Identification of projections of boundary magnetospheric domains from ground

The ULF discriminant of the magnetospheric boundary domains has not been found yet, though many types of “cusp-related” pulsations: IPCL, Pc5, Pc3, were reported. Validation of the ground technique can be made with the use of SuperDARN radars.

As an example, we have verified this approach using small magnetometer array at Svalbard and SuperDARN radar at Hanskalsarmi for cusp-related Pc3 pulsations.

Antarctic SuperDARNRadars andMagnetometers

“Cusp” Pc3 waves at Svalbard array on 2008/02/21

Radar: cusp equatorward boundary at ~76°-77°, beyond magnetometer array.

Latitudinal distribution of Pc3 power is shifted to lower latitudes: peak at 75.3°!

ULF wave power maximum is shifted ~3° southward from the equatorward cusp boundary!

In early studies, the cusp proper was suggested as a conduit of the upstream waves and source of dayside Pc3 pulsations?

“Cusp Pc3 pulsations” are not related to the cusp proper!? A physical mechanism of cusp-related Pc3 ?

Coupling between the magnetotail and polar cap boundary phenomena (PBI, BBF, Pi1/2, ..)

PBI is not only a manifestation of bursty magnetotail activity (BBF, …), but has been found to be a trigger of the substorm onset [Nishimura, 2010]!

Is there a ground magnetic image of PBI activity? Global ULF mode (~25 min) [Lyons, 2002], Pi2 [Sutcliffe, 2003]?

What is the correspondence between the magnetotail fast flows, PBI, Alfvenic aurora, and Pi1B wave burst?

Fine time/spatial structure of substorm onset from multi-instrument Antarctic observations: 5 minutes before and after

Initial substorm brightening can be provided by Alfven wave-driven aurora, correlated with Pi1B pulsations. Pi1B can be used both for timing of onset, and the location of the substorm “epicenter”.

Auroral kilometric radiation (AKR) during onset develops explosively above a preexisting (~1–3 m) low-altitude AKR source. ‘‘AKR breakup’’ suggests an abrupt (4 orders in 30 s!) formation of a new auroral acceleration region (AAR). The development of the low-altitude AAR is a necessary condition for the bursty ignition of high-altitude AAR.

Can this fine structure of onset be revealed from ground ULF observations?

High latitude multi-instrument observations:- ULF Pi2 and Pi1B- AKR (ground array) [LaBelle, 2010]!- VLF, riometer, auroral imager,….

Example of the fine structure of the substorm onset and related ULF activity [Morioka et al., 2008]

Location of the substorm “epicenter” Onset location can be determined from ground data:- Pi2 current structure- Pi1 burst location- Pc1 polarization goniometer- AKR triangulation

ULF onset (before s/s onset!) times from CARISMA (AWESOME) [Rae, 2004]

advanced version of AWESOME algorithm

Pi1 burst location determined by the emission tomography method from seismology)

TCVTCV = well-known and most easily evident signature of the impulsive SW - magnetosphere interaction. TCV is known to be accompanied by burst of Pc1 waves.

Have the TCV-related Pc1 bursts, SSC-related Pc1 bursts, and ordinary EMIC waves the same physical mechanism?

TCV as a local particle accelerator: Is there a TCV-related spot of proton or electron aurora, or riometer burst?

Specific High-latitude ULF Waves and TransientsThe virtue of the Antarctic array of stations is the opportunity to monitor ULF wave activity along a trans-polar chain from mid-latitudes deep into the polar cap. This makes it possible to examine the wave coupling between different regions of the magnetosphere. Polar cap is not a quiet place: Monochromatic Pc3 waves deep inside the polar cap [De Lauretis, 2005]

Polar cap Pi3 pulsationsSpecific polar cap long-period variations (T~4-20 min) have been revealed unambiguously with the cross-spectral analysis of 2D distributions of wave parameters from Antarctic stations [Yagova et al., 2002,2004; Pilipenko et al., 2004]. Picap3 variations are independent of cusp and auroral pulsations (not Pc5!): These polar cap-associated pulsations are coherent within the polar cap night side, and low coherent with auroral and/or cusp disturbances.

The polar cap Picap3 signals are probably related to waves/transients in the tail lobes or global oscillations of night-side magnetosphere?

Example of Pi3 pulsations in the polar cap (P5, P6)

Non-conjugate long-period Pi3 waves in the polar capsNon-conjugate long-period Pi3 waves in the polar caps

Antarctic magnetometers (P5, P6) indicate the occurrence of specific Pi3 pulsations in the polar cap with periods ~20 min.

Arctic polar cap magnetometers (ALE, THL) reveal no signature of simultaneous oscillations!?

Probable Geophysical InterpretationProbable Geophysical Interpretation

In the high-latitude magnetosphere the propagation of Alfven waves can be significantly affected by local variations in the B geometry: An Alfvenic quasi-resonator may occur due to partial AW reflection from a region with rapid changes of B geometry [Pilipenko, 2005] or with high -value and curvature [Mager, 2009]. Wave branches in a high- plasma in a curved B shows the occurrence of a non-propagation band for the Alfven-type mode. May oscillations of only a part of field line are excited? Alfven quasi-resonator along extended field lines Alfven quasi-resonator along extended field lines between polar ionosphere & current sheet/magnetopause? Nbetween polar ionosphere & current sheet/magnetopause? Non-conjugate oscillations? However, predictions of those models should be further verified, both experimentally and numerically with more realistic models and high-latitude conjugate observations.

Alfven-type mode

Support for the upcoming satellite and balloon campaignsBARREL (Balloon Array for RBSP Relativistic Electron Losses) is a study of losses from Earth's radiation belts. BARREL will consist of two Antarctic balloon campaigns conducted in 2012 and 2013. During each campaign, 20 small balloon payloads will be launched from the SANAE IV and the Halley Bay to an altitude of ~30 km with scintillator to measure the bremsstrahlung X-rays produced by precipitating relativistic electrons.

Can EMIC waves damp magnetospheric relativistic electrons?

Upcoming satellite missions: RBSP (NASA) Orbitals (Canada) Relec, Resonance (Russia)

Syowa Station: - Magnetic variation with a fluxgate magnetometer (1-s) and unmanned low power magnetometer network (Skallen, Cape Omega, H100, Dome-F); - Auroral spectroscopic observation: ASC imager (557.7, 630.0, 427.8 nm), All-sky TV camera, Multi-color meridian scanning photometer, - Imaging 1 Hz Riometer (8 x 8 dipole antenna) which covers the area of 180km x 180km at D region altitude;- 1-100Hz Electromagnetic Wave Observation;- SuperDARN radar (Syowa-South and Syowa-East); Conjugate observation at Iceland at Syowa, including fluxgate and induction magnetometers, imaging riometer, VLF receiver, all-sky CCD imager at stations Husafell, Tjornes, and Aedey.

National Institute of Polar Research (Japan)

operates 4 stations throughout the year in Antarctic:Bird Island, King Edward Point, Rothera, Halley, + biological research center & logistics facilities + Ny-Ålesund research station in the Arctic.

Various instruments for Sun Earth Connections Programme

Low Power Magnetometers (1 sec) operate unmanned all year round

British Antarctic Survey (BAS)

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