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Data for Comparison with BU Imagers

Wide-Latitude Substorm Study (WLS)- April 1997

The Wide-Latitude Substorm Study has been organized by the NSF/UAF community as a research interval directed towards providing distributed observations of ionospheric parameters and electrodynamics through coordinated incoherent scatter radar (ISR) observations during active conditions. The WLS experiment is the first ISR World Day to utilize a floating schedule. The dates for the WLS campaign have been selected using the best prediction of recurrent geomagnetic activity, approximately one month before the nominal early-April, 1997 time window.
Long-lived solar-coronal features produce recurrent geomagnetic activity at the (nominal) 27-day solar rotation period. A plot of the recent recurrent Ap index has been used to identify the interval beginning April 8, 1997 as the most likely for the appropriate disturbed conditions. This interval coincided with the fixed UARC coordinated observations/modeling interval.
Because of the general low level of solar and geomagnetic activity at this stage of the solar cycle, synoptic observing modes - providing wide spatial coverage - will be run at the ISR sites. WLS radar operations were scheduled at all sites for 20 UT April 8, 1997 - 20 UT April 10, 1997 and actual operations time varied depending on the capability to extend the experiment outside the nominal 48-hour window. (Millstone Hill coverage extended through April 6-12, 1997 and included the pre-storm and storm intervals.)

Excellent data obtained during the severe storm on the night of April 10-11, 1997 UT

Minor-storm onset @ 22 UT 4/10/97 with major intensification near 04 UT on 04/11/97.

Millstone Hill Observations of April 11, 1997 Storm

These are real-time analysis radar data and final calibration of Ne has not been performed.
Spectral data (temperatures, velocity) between 00UT - 08UT may be contaminated by coherent backscatter

Sondrestrom ISR Observations of April 11, 1997 Storm

Radar observations of local ionosphere and electrodynamic parameters from Sondrestrom

Inst Solar Terr. Phys Irkutsk ISR Observations

Radar observations of local ionospheric ion and electron temperature over Irkutsk for April 8-10, 1997.
Temperatures and upward ion velocity at altitudes of 257 km and 360 km above Irkutsk.
Profiles of plasma frequency derived with the Faraday-rotation technique.

DMSP F12 Observations of April 11, 1997 Storm

Satellite overflights near Millstone Hill, which is at 55 magnetic latitude in the dusk/pre-midnight sector (left side of DMSP plots). Precipitation boundary stays immediately poleward of Millstone Hill throughout intense event.

POLAR Images

An interesting substorm sequence was imaged by the POLAR UVI between 17:11 - 17:41 UT on April 9, 1997. Accompanying GPS TEC movie shows the evolution of poleward-propagation storm-enhanced density SED.
Substorm accompanying predicted 'CME' impact @ 00 UT April 10, 1997.
Representative POLAR UVI images during April 11, 1997 storm

Solar Particles & Fields

A recent plot of solar X-ray flux indicates a solar burst midday on April 7.
Solar wind density has increased daily through the WLS period, reaching >15 cm-3 with bursts to 25 cm-3 on April 10th.
Plot of April 8, 1997 UT WIND RT solar wind parameters.
Plot of April 9, 1997 UT WIND RT solar wind parameters.
Plot of April 10, 1997 UT WIND RT solar wind parameters.
Plot of April 5, 1997 UT WIND SWE Plasma parameters.
Plot of April 6, 1997 UT WIND SWE Plasma parameters.
Plot of April 7, 1997 UT WIND SWE Plasma parameters.
Plot of April 8, 1997 UT WIND SWE Plasma parameters.
Plot of April 9, 1997 UT WIND SWE Plasma parameters.
Plot of April 10, 1997 UT WIND SWE Plasma parameters.
Plot of April 11, 1997 UT WIND SWE Plasma parameters.


WLS experiment operations at Millstone Hill were begun at 20 UT on Saturday, April 5, 1997 in response to the alert of a CME directed towards the Earth and emitted from the solar corona on April 1, 1997. Operations were continued using the wide-coverage mode until 20 UT on April 11, 1997.
Azimuth scan data have been run throughout the WLS campaign, providing spatial latitude/local time coverage across the sub-auroral ionosphere poleward of Millstone Hill.
Azimuth scan data can be seen in detail through the Millstone Hill realtime plots. Millstone saw some perturbation of velocity poleward of the site accompanying the substorm near 17 UT on 4/9/97 (data are very rough due to real-time processing).
http://www.haystack.edu/~jcf/wls97.htm -- Revised: June 26, 1998.jcf@haystack.mit.edu

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