Electric and magnetic fields measured during a sudden impulse

Schutz, S.; Adams, G. J.; Mozer, F. S.

doi:10.1029/ja079i013p02002

Cited by 8 publications

(3 citation statements)

References 9 publications

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“…Geomagnetic sudden impulse generated hydromagnetic waves propagate toward the Earth through the magnetospheric plasma. Schutz et al (1974) have shown that electric fields are generated in the ionosphere as a result of the interaction of the hydromagnetic waves with the ionosphere and these electric fields drive the ionospheric currents which ground-based magnetometers detect as sudden increase in the horizontal north-south geomagnetic field, which is known as SC or sudden impulse (SI).…”

Section: Introductionmentioning

confidence: 99%

Amplitude enhancement of events in the South Atlantic anomaly region

Trivedi¹,

Abdu

Pathan

et al. 2005

Journal of Atmospheric and Solar-Terrestrial Physics

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Section: Introductionmentioning

confidence: 99%

Amplitude enhancement of events in the South Atlantic anomaly region

Trivedi¹,

Abdu

Pathan

et al. 2005

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Those solar phenomena are known for having remarkable signatures in the measurements made outside the magnetosphere (Allen, 1944;Gonzalez et al, 1994;Gopalswamy, 2016;Gopalswamy et al, 2009;Obayashi, 1964;Wilson et al, 2007) as well as for producing clear sudden effects on magnetic measurements at the ground level (Araki, 1994;Curto et al, 2007;Gold, 1962;Matsushita, 1962;Shinbori et al, 2010). The explanation for these magnetic records came with the early work published by Schutz et al (1974). They stated that geomagnetic SI generated hydromagnetic waves that propagate toward the Earth through the plasma of the magnetosphere.…”

Section: Response Of the Embrace Magnet To The Space Weather Driversmentioning

confidence: 99%

The Embrace Magnetometer Network for South America: First Scientific Results

et al. 2018

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The present work is the second of a two‐part paper on the Embrace Magnetometer Network. In this part, we provide some of the first scientific findings that we have already achieved with this network. We identified the diurnal and the seasonal natural variations of the H component. We provided the precise determination of sudden storm commencements and sudden impulse. We showed that the ΔH amplitudes derived from the Embrace MagNet during intense magnetic storm are in very good agreement with the Dst index. We showed that it is possible to investigate the effects on the solar quiet ionospheric current systems as a response to the X‐class solar flares occurring during daytime under magnetically quiet conditions.

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“…The physical processes involved in the electric field's penetration to low latitudes with its partial screening at the internal boundary of the plasma sheet and at the plasmapause are not yet clarified enough to provide quantitative predictions for the region of the equatorial ionospheric anomaly [see Jaggi and Wolf, 1973;Mozer, 1973;Gatperin et al, 1975;Guret)ich et al, 1976;Stern, 1977]. But at least for an ac component of the electric field with periods from tens of minutes to about 1 hour the possibility of a propagation down to low latitudes is well grounded.…”

mentioning

confidence: 99%

Equatorial ionospheric anomaly and interplanetary magnetic field

Galperin¹,

Пономарев²,

Zosimova³

1978

J. Geophys. Res.

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Measurements of the ion convection velocity (transverse horizontal and vertical components) from asymmetry of the lateral ion flow in the satellite frame and also of the total ion concentration were conducted in October-November 1967 from the Cosmos 184 satellite (circular orbit at 630 km, inclination 81ø2'). In this study, first the cases were selected when a reversal of the sign of the By component of the IMF had taken place during the time interval between two successive satellite passes through the equatorial ionospheric anomaly (11 cases). Systematic decreases of the near-equatorial ion density were observed after reversals from By negative to By positive. These decreases were accompanied by relative enhancements of the upward and the eastward components of the plasma drift velocity of the order of several tens of meters per second. Variations of the opposite direction were observed (though less regularly) after By reversals from positive to negative. Important vertical and horizontal plasma drift velocities appear in the irregular density variations and especially at localized ionization spikes (downward velocity relative to surrounding plasma) and dropouts (upward relative velocity). These density dropouts are very similar to the 'plasma bubbles' reported by McClure et al. (1977) and at 630 km are observed mostly when the density profile has a near-equatorial valley. It was shown by Heppner (1972) that the polar cap convection pattern depends on the sign of the By IMF component. If follows that suitably selected polar plasma drift data from Cosmos 184 can also be used to find the pairs of orbits indicating the reversals of By IMF ('inferred reversals'). Typical signatures of the plasma drift pattern in the noon region close to the southern (sunlit) dayside polar cusp were constructed from the whole set of Cosmos 184 data. These signatures indeed show high correlation with the sign of By IMF. The reversal of typical signatures on a pair of successive orbits in fact represents the direct indication of the large-scale electric field variation in the polar ionosphere/outer magnetosphere presumably induced by the reversals of By IMF (9 cases partly overlapping the 11 cases mentioned above). The two sets of data (pairs of orbits) are in general accord (with several doubtful cases but no direct contradictions) both with respect to the By sign reversal evaluation and with respect to the above-described differential variations in the latitudinal ion density profiles and in the plasma drift velocities in the equatorial ionospheric anomaly. These observations confirm the propagation of the electric field variations from polar ionosphere/outer magnetosphere down to the equatorial latitudes, as was suggested by Rastogi and Patel (1975).

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Electric and magnetic fields measured during a sudden impulse

Cited by 8 publications

References 9 publications

Amplitude enhancement of events in the South Atlantic anomaly region

Amplitude enhancement of events in the South Atlantic anomaly region

The Embrace Magnetometer Network for South America: First Scientific Results

Equatorial ionospheric anomaly and interplanetary magnetic field

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