| 1. |
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| 2. |
- Janhunen, P, et al.
(author)
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A study of inverted-V auroral acceleration mechanisms using Polar/Fast Auroral Snapshot conjunctions
- 2001
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In: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - : AMER GEOPHYSICAL UNION. - 0148-0227. ; 106:A9, s. 18995-19011
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Journal article (peer-reviewed)abstract
- We present observations of electrons and ions that have been affected by an auroral plasma acceleration mechanism. In the nine events studied, nearly simultaneous and magnetically conjugate measurements were made by instruments on the Fast Auroral Snapsho
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| 3. |
- KAURISTIE, K, et al.
(author)
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ANALYSIS OF THE SUBSTORM TRIGGER PHASE USING MULTIPLE GROUND-BASED INSTRUMENTATION
- 1995
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In: GEOPHYSICAL RESEARCH LETTERS. - : AMER GEOPHYSICAL UNION. - 0094-8276. ; 22:15, s. 2065-2068
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Journal article (other academic/artistic)abstract
- During the substorm trigger phase, i.e. during the last few minutes before the onset, the slowly and linearly developing growth phase features strengthen exponentially. Often the enhanced auroral activity fades abruptly during a couple of minutes just pri
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| 4. |
- Kauristie, K, et al.
(author)
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Auroral precipitation fading before and at substorm onset: ionospheric and geostationary signatures
- 1997
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In: ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES. - : SPRINGER VERLAG. - 0992-7689. ; 15:8, s. 967-983
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Journal article (other academic/artistic)abstract
- Rapid fading of auroral activity a few minutes before substorm breakup has earlier been analyzed in case-studies. Here we report on a study in which all-sky camera (ASC) and magnetic data over 3 years were examined to find breakups that were accompanied b
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| 5. |
- Kauristie, K, et al.
(author)
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What can we tell about global auroral electrojet activity from a single meridional magnetometer chain?
- 1996
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In: ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES. - : SPRINGER VERLAG. - 0992-7689. ; 14:11, s. 1177-1185
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Journal article (other academic/artistic)abstract
- The AE indices are generally used for monitoring the level of magnetic activity in the auroral oval region. In some cases, however, the oval is either so expanded or contracted that the latitudinal coverage of the AE magnetometer chain is not adequate. Th
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| 6. |
- PELLINEN, RJ, et al.
(author)
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THE TRIGGER PHASE OF MAGNETOSPHERIC SUBSTORMS
- 1994
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In: GEOMAGNETIZM I AERONOMIYA. - : MEZHDUNARODNAYA KNIGA. - 0016-7940. ; 34:6, s. 1-8
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Journal article (other academic/artistic)abstract
- The last few minutes of the substorm growth phase before the auroral breakup show features distinct both from the gradual growth phase development and from the rapidly evolving expansion phase. During this time the optical auroras fade, energetic particle
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| 7. |
- Persson, M. A. L., et al.
(author)
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Near-Earth substorm onset - a coordinated study
- 1994
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In: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 21:17, s. 1875-1878
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Journal article (peer-reviewed)abstract
- We present simultaneous satellite and ground-based measurements of a substorm. Throughout the initial substorm expansion, southward drifting arcs are observed poleward of the expanding substorm aurora, indicating two independent systems of particle precipitation. Freja passes the brightening onset arc in the topside ionosphere near the moment of the substorm onset, observing an Alfven wave, field aligned current and oxygen ion outflow. The substorm onset occurs at low magnetospheric L-shells, near the poleward edge of the region of trapped particles. The location and time for the substorm injection are confirmed by geostationary spacecraft together with magnetometers, all-sky cameras and radar on the ground. We believe that the substorm onset may be triggered by modification of the oxygen content of the inner magnetosphere during the growth-phase caused by ionospheric ion outflow.
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| 8. |
- Pulkkinen, TI, et al.
(author)
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Two substorm intensifications compared: Onset, expansion, and global consequences
- 1998
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In: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - : AMER GEOPHYSICAL UNION. ; 103:A1, s. 15-27
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Journal article (other academic/artistic)abstract
- We present observations of two sequential substorm onsets on May 15, 1996. The first event occurred during persistently negative IMF B-Z, whereas the second expansion followed a northward turning of the interplanetary magnetic field (IMF). While the first
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