1,007 research outputs found
Evolution of kinklike fluctuations associated with ion pickup within reconnection outflows in the Earth's magnetotail
Magnetic reconnection (MR) in Earth's magnetotail is usually followed by a
systemwide redistribution of explosively released kinetic and thermal energy.
Recently, multispacecraft observations from the THEMIS mission were used to
study localized explosions associated with MR in the magnetotail so as to
understand subsequent Earthward propagation of MR outbursts during substorms.
Here we investigate plasma and magnetic field fluctuations/structures
associated with MR exhaust and ion-ion kink mode instability during a well
documented MR event. Generation, evolution and fading of kinklike oscillations
are followed over a distance of 70 000 km from the reconnection site in the
midmagnetotail to the more dipolar region near the Earth. We have found that
the kink oscillations driven by different ion populations within the outflow
region can be at least 25 000 km from the reconnection site.Comment: 11 pages, 4 figure
Characteristics of ion flow in the quiet inner plasma sheet
Abstract
We use AMPTE/IRM and ISEE 2 data to study the properties of the high beta (βi \u3e 0.5) plasma sheet, the inner plasma sheet (IPS). Bursty bulk flows (BBFs) are excised from the two databases, and the average flow pattern in the non-BBF (quiet) IPS is constructed. At local midnight this ensemble-average flow is predominantly duskward; closer to the flanks it is mostly earthward. The flow pattern agrees qualitatively with calculations based on the Tsyganenko [1987] model (T87), where the earthward flow is due to the ensemble-average cross tail electric field and the duskward flow is the diamagnetic drift due to an inward pressure gradient. The IPS is on the average in pressure equilibrium with the lobes. Because of its large variance the average flow does not represent the instantaneous flow field. Case studies also show that the non-BBF flow is highly irregular and inherently unsteady, a reason why earthward convection can avoid a pressure balance inconsistency with the lobes. The ensemble distribution of velocities is a fundamental observable of the quiet plasma sheet flow field
Magnetic flux transfer in the 5 April 2010 Galaxy 15 substorm: an unprecedented observation
At approximately 08:25 UT on 5 April 2010, a CME-driven shock compressed
Earth's magnetosphere and applied about 15 nT of southward IMF for nearly an
hour. A substorm growth phase and localized dipolarization at 08:47 UT were
followed by large dipolarizations at 09:03 UT and 09:08 UT, observed by GOES
West (11) in the midnight sector, and by three THEMIS spacecraft near X=−11,
Y=−2 RE. A large electric field at the THEMIS spacecraft indicates so
much flux transfer to the inner magnetosphere that "overdipolarization" took
place at GOES 11. This transfer is consistent with the ground and space
magnetic signature of the substorm current wedge. Significant particle
injections were also observed. The ensemble of extreme geophysical
conditions, never previously observed, is consistent with the Near-Earth
Neutral Line interpretation of substorms, and subjected the Galaxy 15
geosynchronous satellite to space weather conditions which appear to have
induced a major operational anomaly
Sebaceous gland tumors and internal malignancy in the context of Muir-Torre syndrome. A case report and review of the literature
BACKGROUND: The Muir-Torre syndrome is a rare autosomal dominant condition and is currently considered a subtype of the more common hereditary nonpolyposis colorectal cancer syndrome, in which multiple primary malignancies occur together with sebaceous gland tumors. CASE PRESENTATION: We describe a case of a 62-year-old woman with three primary colorectal tumors, genital tumor, and sebaceous adenomas and present her family history of three generations. Our case represents the first case reported from Greece in the international literature. CONCLUSION: Recognition of the syndrome in patients with sebaceous gland tumors should facilitate early detection of subsequent malignancies if the patient is entered into appropriate screening programs
A statistical study of the inner edge of the electron plasma sheet and the net convection potential as a function of geomagnetic activity
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94691/1/jgra21076.pd
Cusp plasma intrusion and Pc 5
第2回極域科学シンポジウム/第35回極域宙空圏シンポジウム 11月16日(水) 統計数理研究所 3階リフレッシュフロ
THEMIS Observations of Directly-Driven Pi2 Pulsations
The THEMIS tail seasons have provided an unprecedented opportunity to examine the causal relationship between midtail plasma flows and low latitude Pi2 pulsations. We present several events where multiple THEMIS spacecraft observed magnetotail flow bursts which were followed up to several minutes later by ground Pi2 pulsations. We find good agreement with the waveforms of the flow bursts and flank Pi2, in agreement with the hypothesis that Pi2 at low-latitude on the flank are directly-driven by periodic variations in the flow bursts. For at least I event we are able to follow the Pi2 impulses from the periodic flow bursts on the nightside. to ground Pi2 at the flanks, and finally through the dayside magnetosphere as observed by GOES. We further place the physical mechanism generating these Pi2 into the context of sub storm onset. We conclude by discussing the sequence and coupling of events that are necessary to explain the correlation, and the constraints this places on models of transient magnetospheric transport
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Timing and localization of ionospheric signatures associated with substorm expansion phase onset
In this paper, we present case studies of the optical and magnetic signatures of the characteristics of the first minute of substorm expansion phase onset observed in the ionosphere. We find that for two isolated substorms, the onset of magnetic pulsations in the 24–96 s period wavelet band are colocated in time and space with the formation and development of small-scale optical undulations along the most equatorward preexisting auroral arc prior to auroral breakup. These undulations undergo an inverse spatial cascade into vortices prior to the release of the westward traveling surge. We also present a case study of a multiple activation substorm, whereby discrete onsets of ULF wave power above a predetermined quiet time threshold are shown to be associated with specific optical intensifications and brightenings. Moreover, in the multiple activation substorm event, we show that neither the formation of the small-scale undulations nor the formation of similar structures along a north–south aligned arc is sufficient to produce auroral breakup associated with expansion phase onset. It is only ∼10 min after these two disparate activation regions initiate that auroral breakup and the subsequent formation of a westward traveling surge occur. We discuss the implications of these results in terms of the triggering mechanisms likely to be occurring during these specific events
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