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B T Tsurutani - One of the best experts on this subject based on the ideXlab platform.
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extreme changes in the dayside ionosphere during a carrington type Magnetic Storm
Journal of Space Weather and Space Climate, 2012Co-Authors: B T Tsurutani, O P Verkhoglyadova, Anthony J Mannucci, G S Lakhina, J D HubaAbstract:It is shown that during the 30 October 2003 superStorm, dayside O + ions were uplifted to DMSP altitudes (~850 km). Peak densities were ~9 · 10 5 cm 3 during the Magnetic Storm main phase (peak Dst = 390 nT). By comparison the 1–2 September 1859 Carrington Magnetic Storm (peak Dst estimated at 1760 nT) was considerably stronger. We investigate the impact of this Storm on the low- to mid-latitude ionosphere using a modified version of the NRL SAMI2 ionospheric code. It is found that the equatorial region (LAT = 0� ±1 5� ) is swept free of plasma within 15 min (or less) of Storm onset. The plasma is swept to higher altitudes and higher latitudes due to E · B convection associated with the prompt penetration electric field. Equatorial Ionization Anomaly (EIA) O + density enhancements are found to be located within the broad range of latitudes ~ ± (25� –40� ) at ~500–900 km altitudes. Densities within these peaks are ~6 · 10 6 oxygen ions-cm 3 at ~700 km altitude, approximately +600% quiet time values. The oxygen ions at the top portions (850–1000 km) of uplifted EIAs will cause strong low-altitude satellite drag. Calculations are currently being performed on possible uplift of oxygen neutrals by ion-neutral coupling to understand if there might be further significant satellite drag forces present.
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simultaneous satellite observations of vlf chorus hot and relativistic electrons in a Magnetic Storm recovery phase
Geophysical Research Letters, 2009Co-Authors: Yoshiya Kasahara, B T Tsurutani, O P Verkhoglyadova, Yoshizumi Miyoshi, Yoshiharu Omura, Isamu Nagano, Ikuo KimuraAbstract:[1] The mechanism for formation of the Earth's radiation belts has been an outstanding issue for utilization of the geospace environment. We present a Magnetic Storm recovery phase that occurred from 10 to 19 October 1990, in which there is a clear correlation among continuous injection of hot electrons, generation of chorus, geoMagnetic AE activity (all for ∼8 days) and the acceleration of electrons to relativistic energies. We propose a following scenario to explain the observations: the continuous injection of hot electrons associated with the continuous AE activity. The hot electrons with Tperp/Tpara > 1 temperature anisotropies excite whistler-mode chorus waves. The chorus interacts with energetic electrons accelerating them to MeV energies forming a flux of “killer electrons” in the outer radiation belt.
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prompt penetration electric fields ppefs and their ionospheric effects during the great Magnetic Storm of 30 31 october 2003
Journal of Geophysical Research, 2008Co-Authors: Akinori Saito, K Yumoto, B T Tsurutani, O P Verkhoglyadova, Anthony J Mannucci, Tohru Araki, Toshitaka Tsuda, M A AbduAbstract:[1] We explore the ionospheric effects of prompt penetration electric fields (PPEFs) for a variety of interplanetary Magnetic field directions. We use the great Magnetic Storm of 30–31 October as an example of PPEF effects. For intense southward interplanetary Magnetic fields (IMFs), inward plasma sheet convection occurs with the result of magnetospheric ring current formation and an intense Magnetic Storm. Concurrent with the above, positive phase ionospheric Storms occur in the dayside, and negative phase ionospheric Storms occur on the nightside, the topics of this paper. The dayside ionospheric Storms due to PPEFs are characterized by transport of near-equatorial plasma to higher altitudes and latitudes, forming a giant plasma fountain. These features are part of what is called the dayside ionospheric superfountain (DIS). For these southward IMFs, dusk and dawn plasma are predicted to be transported toward the dayside. For northward IMFs, negative phase ionospheric Storms are expected on the dayside if the PPEFs indeed reach that region of space. IMF By components are expected to have weak or neglible ionospheric effects. On the basis of PPEF arguments, intervals of IMF By should not be related to geoMagnetic Storms (they are not). IMF By intervals should, however, cause a shearing of the magnetotail, a feature that has been previously reported in the literature.
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modeling of 1 2 september 1859 super Magnetic Storm
Advances in Space Research, 2006Co-Authors: M Temerin, B T Tsurutani, S AlexAbstract:Abstract Based on an estimated solar wind condition around 1–2 September 1859, we were able to reproduce the Carrington Magnetic Storm magnetometer record, with the H-component depression of −1600 nT, made at Colaba Observatory in Mumbai, India. We used an updated Dst prediction model from Temerin and Li (2002) , which provides a prediction efficiency of 0.91 for 1995–2002 interval using a fixed set of modeling parameters. The negative depression in the magnetometer record could be explained by assumptions as to the condition of the solar wind that, though far more geoeffective than any that have ever been observed, do not seem improbable given the known average speed of the interplanetary shock for this event. The extremely fast recovery of the magnetometer record, however, required that the dynamic pressure of the solar wind also be substantially larger than has ever been observed. We also showed how the strength of the Magnetic Storm would have depended on the season and the time of day. For the same solar wind conditions in GSM coordinates, the largest Magnetic Storms occur around the fall equinox and at the time of day when the dipole axis is most perpendicular to the solar wind velocity. Given the assumed very fast solar wind with a very large negative interplanetary Magnetic field (IMF) B z directly impacting the Earth, our model together with the known magnetometer record indicates that a super Magnetic Storm with minimum Dst less than −1600 nT could have occurred and thus can occur again. For the Magnetic Storm of 1–2 September 1859, however, the extremely fast recovery of Dst requires an extremely large pressure enhancement. This suggests that this particular event was doubly unusual.
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self consistent modeling of the large scale distortions in the geoMagnetic field during the 24 27 september 1998 major Magnetic Storm
Journal of Geophysical Research, 2005Co-Authors: Ya I Feldstein, B T Tsurutani, W D Gonzalez, J U Kozyra, A E Levitin, A Prigancova, L Alperovich, U Mall, I I Alexeev, L I GromovaAbstract:[1] A new self-consistent version of a time-dependent magnetospheric paraboloid model is presented and tested on the 24–27 September 1998 Magnetic Storm interval (minimum Dst = −207 nT). The model uses DMSP satellite data to identify the location of the inner boundary of the magnetotail current sheet and the Magnetic flux in the lobes and their variations with time. These inputs plus upstream solar wind dynamic pressure and IMF Bz values are used to iteratively model the Earth's field during the Storm. Several interesting results with important consequences are obtained: (1) the model tail field strength at the Earth's surface (DT = −134 nT) is a significant fraction of the ring current value (DR = −167 nT); (2) the movement of the tail current sheet inward to L = 3.5–4.0 at Storm maximum is consistent with geosynchronous Magnetic field data; (3) at the Earth's surface the Chapman-Ferraro magnetopause current field (DCF = 117 nT) is almost equal at Storm maximum to the value from the tail current, thus the fields from the two systems nearly cancel; (4) the Magnetic flux from the polar cap in the course of the Magnetic Storm main phase approximately doubles in comparison with the magneto-quiet interval just before the Storm onset; this fact shows that the driven processes prevail over dissipation processes throughout the Storm main phase; (5) the large-scale internal currents in the magnetosphere (ring current, field-aligned currents, and magnetotail current) have significant influence on the shape and size of the magnetosphere; the location of the magnetopause subsolar point is different from that obtained by extrapolation of empirical results taken during high geoMagnetic activity intervals and from magnetospheric models that do not include feedback from internal magnetospheric currents.
S Basu - One of the best experts on this subject based on the ideXlab platform.
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response of the equatorial ionosphere in the south atlantic region to the great Magnetic Storm of july 15 2000
Geophysical Research Letters, 2001Co-Authors: S Basu, K M Groves, S Y Su, F J Rich, P J Sultan, M J KeskinenAbstract:The effects of the great Magnetic Storm of July 15, 2000 on the equatorial ionosphere have been studied by ground-based and satellite in-situ measurements. A large westward plasma drift in the evening equatorial ionosphere was observed as a result of the ionospheric disturbance dynamo. In that environment, the IMF Bz turned southward and presumably caused penetration of E-fields to low latitudes. This E-field initiated the onset of 250 MHz and L-band scintillations at Ascension Island (15°W) and precipitous TEC decrease at Fortaleza, Brazil (38°W), bounding the narrow longitude region in the South Atlantic. These impulsive ionospheric effects were extremely well correlated with abrupt decreases of SYM-H (1-min resolution Dst). The DMSP in-situ measurements showed the presence of severe ion density bite-outs extending over 30° latitude in the South Atlantic Magnetic Anomaly region. The ROCSAT-1 satellite measured upward and large southward ion drifts in the same sector.
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response of the equatorial ionosphere in the south atlantic region to the great Magnetic Storm of july 15 2000
Geophysical Research Letters, 2001Co-Authors: S Basu, K M Groves, F J Rich, P J Sultan, H C Yeh, M J KeskinenAbstract:The effects of the great Magnetic Storm of July 15, 2000 on the equatorial ionosphere have been studied by ground-based and satellite in-situ measurements. A large westward plasma drift in the evening equatorial ionosphere was observed as a result of the ionospheric disturbance dynamo. In that environment, the IMF Bz turned southward and presumably caused penetration of E-fields to low latitudes. This E-field initiated the onset of 250 MHz and L-band scintillations at Ascension Island (15°W) and precipitous TEC decrease at Fortaleza, Brazil (38°W), bounding the narrow longitude region in the South Atlantic. These impulsive ionospheric effects were extremely well correlated with abrupt decreases of SYM-H (1-min resolution Dst). The DMSP in-situ measurements showed the presence of severe ion density bite-outs extending over 30° latitude in the South Atlantic Magnetic Anomaly region. The ROCSAT-1 satellite measured upward and large southward ion drifts in the same sector.
M J Keskinen - One of the best experts on this subject based on the ideXlab platform.
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response of the equatorial ionosphere in the south atlantic region to the great Magnetic Storm of july 15 2000
Geophysical Research Letters, 2001Co-Authors: S Basu, K M Groves, S Y Su, F J Rich, P J Sultan, M J KeskinenAbstract:The effects of the great Magnetic Storm of July 15, 2000 on the equatorial ionosphere have been studied by ground-based and satellite in-situ measurements. A large westward plasma drift in the evening equatorial ionosphere was observed as a result of the ionospheric disturbance dynamo. In that environment, the IMF Bz turned southward and presumably caused penetration of E-fields to low latitudes. This E-field initiated the onset of 250 MHz and L-band scintillations at Ascension Island (15°W) and precipitous TEC decrease at Fortaleza, Brazil (38°W), bounding the narrow longitude region in the South Atlantic. These impulsive ionospheric effects were extremely well correlated with abrupt decreases of SYM-H (1-min resolution Dst). The DMSP in-situ measurements showed the presence of severe ion density bite-outs extending over 30° latitude in the South Atlantic Magnetic Anomaly region. The ROCSAT-1 satellite measured upward and large southward ion drifts in the same sector.
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response of the equatorial ionosphere in the south atlantic region to the great Magnetic Storm of july 15 2000
Geophysical Research Letters, 2001Co-Authors: S Basu, K M Groves, F J Rich, P J Sultan, H C Yeh, M J KeskinenAbstract:The effects of the great Magnetic Storm of July 15, 2000 on the equatorial ionosphere have been studied by ground-based and satellite in-situ measurements. A large westward plasma drift in the evening equatorial ionosphere was observed as a result of the ionospheric disturbance dynamo. In that environment, the IMF Bz turned southward and presumably caused penetration of E-fields to low latitudes. This E-field initiated the onset of 250 MHz and L-band scintillations at Ascension Island (15°W) and precipitous TEC decrease at Fortaleza, Brazil (38°W), bounding the narrow longitude region in the South Atlantic. These impulsive ionospheric effects were extremely well correlated with abrupt decreases of SYM-H (1-min resolution Dst). The DMSP in-situ measurements showed the presence of severe ion density bite-outs extending over 30° latitude in the South Atlantic Magnetic Anomaly region. The ROCSAT-1 satellite measured upward and large southward ion drifts in the same sector.
S Alex - One of the best experts on this subject based on the ideXlab platform.
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modeling of 1 2 september 1859 super Magnetic Storm
Advances in Space Research, 2006Co-Authors: M Temerin, B T Tsurutani, S AlexAbstract:Abstract Based on an estimated solar wind condition around 1–2 September 1859, we were able to reproduce the Carrington Magnetic Storm magnetometer record, with the H-component depression of −1600 nT, made at Colaba Observatory in Mumbai, India. We used an updated Dst prediction model from Temerin and Li (2002) , which provides a prediction efficiency of 0.91 for 1995–2002 interval using a fixed set of modeling parameters. The negative depression in the magnetometer record could be explained by assumptions as to the condition of the solar wind that, though far more geoeffective than any that have ever been observed, do not seem improbable given the known average speed of the interplanetary shock for this event. The extremely fast recovery of the magnetometer record, however, required that the dynamic pressure of the solar wind also be substantially larger than has ever been observed. We also showed how the strength of the Magnetic Storm would have depended on the season and the time of day. For the same solar wind conditions in GSM coordinates, the largest Magnetic Storms occur around the fall equinox and at the time of day when the dipole axis is most perpendicular to the solar wind velocity. Given the assumed very fast solar wind with a very large negative interplanetary Magnetic field (IMF) B z directly impacting the Earth, our model together with the known magnetometer record indicates that a super Magnetic Storm with minimum Dst less than −1600 nT could have occurred and thus can occur again. For the Magnetic Storm of 1–2 September 1859, however, the extremely fast recovery of Dst requires an extremely large pressure enhancement. This suggests that this particular event was doubly unusual.
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the extreme Magnetic Storm of 1 2 september 1859
Journal of Geophysical Research, 2003Co-Authors: B T Tsurutani, G S Lakhina, W D Gonzalez, S AlexAbstract:[1] The 1–2 September 1859 Magnetic Storm was the most intense in recorded history on the basis of previously reported ground observations and on newly reduced ground-based Magnetic field data. Using empirical results on the interplanetary Magnetic field strengths of Magnetic clouds versus velocities, we show that the 1 September 1859 Carrington solar flare most likely had an associated intense Magnetic cloud ejection which led to a Storm on Earth of DST ∼ −1760 nT. This is consistent with the Colaba, India local noon Magnetic response of ΔH = 1600 ± 10 nT. It is found that both the 1–2 September 1859 solar flare energy and the associated coronal mass ejection speed were extremely high but not unique. Other events with more intense properties have been detected; thus a Storm of this or even greater intensity may occur again. Because the data for the high-energy tails of solar flares and Magnetic Storms are extremely sparse, the tail distributions and therefore the probabilities of occurrence cannot be assigned with any reasonable accuracy. A further complication is a lack of knowledge of the saturation mechanisms of flares and Magnetic Storms. These topics are discussed in some detail.
H J Singer - One of the best experts on this subject based on the ideXlab platform.
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global observations of magnetospheric high m poloidal waves during the 22 june 2015 Magnetic Storm
Geophysical Research Letters, 2017Co-Authors: P J Chi, K R Bromund, H J Singer, Robert J. Strangeway, B J Anderson, C T Russell, J A Slavin, K Takahashi, D Fischer, E L KepkoAbstract:We report global observations of high-m poloidal waves during the recovery phase of the 22 June 2015 Magnetic Storm from a constellation of widely spaced satellites of five missions including Magnetospheric Multiscale (MMS), Van Allen Probes, Time History of Events and Macroscale Interactions during SubStorm (THEMIS), Cluster, and Geostationary Operational Environmental Satellites (GOES). The combined observations demonstrate the global spatial extent of Storm time poloidal waves. MMS observations confirm high azimuthal wave numbers (m ~ 100). Mode identification indicates the waves are associated with the second harmonic of field line resonances. The wave frequencies exhibit a decreasing trend as L increases, distinguishing them from the single-frequency global poloidal modes normally observed during quiet times. Detailed examination of the instantaneous frequency reveals discrete spatial structures with step-like frequency changes along L. Each discrete L shell has a steady wave frequency and spans about 1 RE , suggesting that there exist a discrete number of drift-bounce resonance regions across L shells during Storm times.
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magnetopause erosion during the 17 march 2015 Magnetic Storm combined field aligned currents auroral oval and magnetopause observations
Geophysical Research Letters, 2016Co-Authors: G. Le, Hermann Lühr, H J Singer, Robert J. Strangeway, B J Anderson, James A. Slavin, C T Russell, Y Zhang, K R BromundAbstract:We present multimission observations of field-aligned currents, auroral oval, and magnetopause crossings during the 17 March 2015 Magnetic Storm. Dayside reconnection is expected to transport Magnetic flux, strengthen field-aligned currents, lead to polar cap expansion and magnetopause erosion. Our multimission observations assemble evidence for all these manifestations. After a prolonged period of strongly southward interplanetary Magnetic field, Swarm and AMPERE observe significant intensification of field-aligned currents .The dayside auroral oval, as seen by DMSP, appears as a thin arc associated with ongoing dayside reconnection. Both the field-aligned currents and the auroral arc move equatorward reaching as low as approx. 60 deg. Magnetic latitude. Strong magnetopause erosion is evident in the in situ measurements of the magnetopause crossings by GOES 13/15 and MMS. The coordinated Swarm, AMPERE, DMSP, MMS and GOES observations, with both global and in situ coverage of the key regions, provide a clear demonstration of the effects of dayside reconnection on the entire magnetosphere.
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april 2000 Magnetic Storm solar wind driver and magnetospheric response
Journal of Geophysical Research, 2002Co-Authors: Emilia K J Huttunen, Antti Pulkkinen, H Koskinen, T I Pulkkinen, Minna Palmroth, Geoffrey E D Reeves, H J SingerAbstract:[1] On 4 April 2000, a coronal mass ejection (CME) took place close to the western limb of the Sun. The shock front of the CME hit the Earth's magnetosphere on 6 April. A strong interplanetary southward BZ event in the sheath region caused a Magnetic Storm that was the second strongest in the year 2000 if quantified by the peak of the Dst index. We have analyzed this sequence of events using observations of several spacecraft in the solar wind and at geostationary orbit as well as recordings from more than 80 magnetometer stations at latitudes higher than 40°N. In the sheath region behind the shock, the interplanetary Magnetic field had an intense and long-sustained southward Magnetic field orientation, and the solar wind Magnetic pressure was very large, which compressed the dayside magnetopause inside geostationary orbit for a period of more than 6 hours. We conclude that it was the fluctuating but strongly southward field accompanied by the high pressure that allowed for the exceptionally strong driving of magnetospheric activity. During the main phase of the Storm, the magnetosphere and ionosphere were in highly perturbed states, with several activations all around the auroral region. Detailed analysis shows that many of these activations were not subStorms, in the sense that they were not associated with poleward and westward electrojet/auroral enhancement or geostationary particle injections, but were directly driven perturbations due to variations in the solar wind features. In fact, it was found that the development of the entire Storm was quite independent of subStorm activations and injections. Instead, the ring current development was driven by the strong convection enhancements. During the Storm, the geoMagnetically induced currents were strongly enhanced during several periods. While some activations were associated with subStorm onsets or electrojet enhancements, others were caused by extremely localized and short-lived electrojet activations.