NSF grants 0806196 and 0806338
Collaborative Research: Continued study of ULF waves at cusp latitudes on Svalbard to probe Earth’s space environment
This proposal supports the continued operation of, and analysis of data from, a closely-spaced array of four search coil magnetometers (induction antennas) installed during September 2006 on Svalbard, Norway, for studies of ULF waves and associated phenomena in Earth’s space environment. On Svalbard, magnetic field lines from the cusp region map to the outer boundary of Earth's magnetosphere, where it interacts with the solar wind and interplanetary magnetic field (IMF). Because of this, ground stations located under the cusp region provide information about the first entry of energy and momentum from the solar wind to Earth's high latitude magnetosphere and ionosphere. An extensive array of instrumentation has been installed on Svalbard, primarily because it is the only readily accessible site in the northern hemisphere where the ionospheric footpoint of the magnetospheric cusp is consistently in darkness during winter solstice. In addition to induction coil magnetometers, installed as part of the this project in 2006, instruments on Svalbard include numerous auroral imagers and photometers, multiple radars including EISCAT, SPEAR, and SuperDARN, and the northernmost stations in the IMAGE array of fluxgate magnetometers. Such a complete suite of instruments enables the association of various features in the observations with specific magnetospheric regions, such as the plasma sheet, low latitude boundary layer, cusp proper, or plasma mantle, with more confidence and reliability than in earlier studies at other locations. The role of induction coil magnetometers is to detect magnetic fluctuations in the middle and upper ULF frequency range (0.02 - 5 Hz), which includes Pc 3 and Pc 1-2 pulsations and irregular Pi 1 activity.
Two-axis search coil magnetometers (induction coils) sample the horizontal components of Earth’s magnetic field at four sites on Svalbard at a rate of 10 s/sec. These data are used to study geomagnetic micropulsations, ultra-low-frequency (ULF) oscillations in Earth’s space environment that are generated as a result of interactions and instabilities in the plasmas in the overhead ionosphere and magnetosphere. These ULF waves are transitory variations of small amplitude (usually less than one part in 10 thousand of the Earth’s magnetic field) and leave no permanent effects on the field. Like longer period disturbances, such as magnetic storms, the energy that drives them is of solar origin, in contrast to the Earth’s main field and secular variations which are of internal origin.
The sensor systems have a frequency response from DC to ~2.5 Hz (-3 dB corner frequency), as a result of filters to reject higher-frequency noise from atmospheric Schumann resonances and electrical mains. The system is scaled to accomodate approximately 4.5 nT Hz, with a bit resolution of ~1 pT Hz and with a noise floor of approximately a few pT^2/Hz.
Station Geographic Corrected Geomagnetic
Lat Lon Lat Lon
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NAL Ny-Ålesund 78.93 11.95 76.30 110.79
LYR Longyearbyen 78.15 16.03 75.29 111.71
HOR Hornsund 77.00 13.70 74.23 109.16
IFR Isfjord Radio 78.08 13.38 75.00 127.35
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Data collection began at the first three sites in September 2006, and at Isfjord Radio in September 2008. The sampling rate is 10 Hz, comprising 43 MB of data per day. Each system is operated continuously after installation, and daily files are written to computer media for electronic transmission to the investigators. Gaps exist in the data record during power failures and, infrequently, due to system failures. Data collection is ongoing.
Each line of the daily ASCII data files contains a time stamp (in seconds of day) and the values of dB/dt (in nanoTeslas/second) in the north-south and east-west directions at that time.
Software in IDL is available from the investigators to produce time series line plots and Fourier spectrograms of the data. Summary Fourier spectrograms are available at http://space.augsburg.edu/space/Svalbard/ and http://mirl.sr.unh.edu/ULF/ULF_dbstatus.php, and on-demand line plots are available at http://mirl.sr.unh.edu/ULF/ULF_plotquery.php
Data may be shared freely. Credit should be given to either of the PIs if they are used for publication.
Contact Information:
Dr. Mark Engebretson, Co-PI
Department of Physics, Augsburg College, 2211 Riverside Avenue, Minneapolis, MN 55454-1338, USA.
engebret@augsburg.edu
+1-612-330-1067 (office) / +1-612-330-1649 (fax)
Dr. Marc R. Lessard, Co-PI
Space Science Center and Department of Physics, University of New Hampshire, 39 College Road, Durham, NH. 03824, USA.
marc.lessard@unh.edu
+1-603-862-2590 (office) /+1-603-862-0311 (fax)
Jennifer L. Posch, Assistant Scientist
Department of Physics Augsburg College, 2211 Riverside Avenue, Minneapolis, MN 55454-1338, USA.
posch@augsburg.edu
+1-612-330-1040 (office) / +1-612-330-1649 (fax)
Paul W. Riley, Research Engineer
Space Science Center, University of New Hampshire, 39 College Road, Durham, NH. 03824, USA.
paul.riley@unh.edu
+1-603-862-2653 (office) / +1-603-862-0311 (fax)
Hyomin Kim, Graduate Student
Space Science Center and Systems Design Engineering, University of New Hampshire, 39 College Road, Durham, NH. 03824, USA.
hyomin.kim@unh.edu
+1-603-862-1391 (office) / +1-603-862-0311 (fax)
Further information is available at these web sites: http://space.augsburg.edu/space/Svalbard/ , and http://mirl.sr.unh.edu/ULF/ULF_svalbard.html