scholarly journals The ionospheric storm studies: further development of the mapping technique

1996 ◽  
Vol 39 (4) ◽  
Author(s):  
I. Kutiev ◽  
T. Samardjiev ◽  
P. A. Bradley ◽  
M. I. Dick ◽  
L. R. Cander
Keyword(s):  
Magnetic Storm ◽  
Recovery Phase ◽  
Main Phase ◽  
Mapping Technique ◽  
Ionospheric Storm ◽  
Further Development

The technique of using instantaneous maps for ionospheric storm studies is further developed. Integral parameters are introduced characterizing the main features of each map. These parameters are the net volumes of ?f0F2, ?M(3000)F2and their gradients. The magnetic storm 1-2 March, 1982 was considered and it was found that before the storm commencement and in recovery phase the Net Gradient (NG) is directed steadily to the East, while in the main phase it turns southward. NG shows where the changes of the F-layer come from. The net volume of ?f0F2 (NF) correlates well with Dst and AE indices.

Does the duration of the magnetic storm recovery phase depend on the development rate in its main phase? 2. A new method

2016 ◽  
Vol 56 (3) ◽  
pp. 276-280 ◽  
Author(s):  
Yu. I. Yermolaev ◽  
I. G. Lodkina ◽  
N. S. Nikolaeva ◽  
M. Yu. Yermolaev
Keyword(s):  
Magnetic Storm ◽  
Recovery Phase ◽  
Development Rate ◽  
Main Phase ◽  
New Method ◽  
Phase 2

Variations of geomagnetic thresholds of cosmic rays and magnetospheric parameters during different phases  of the storm of November 20, 2003

2021 ◽  
Author(s):  
Elena Vernova ◽  
Natalia Ptitsyna ◽  
Olga Danilova ◽  
Marta Tyasto
Keyword(s):  
Solar Wind ◽  
Cosmic Rays ◽  
Hysteresis Loop ◽  
Magnetic Storm ◽  
Cosmic Ray ◽  
Recovery Phase ◽  
Main Phase ◽  
Cutoff Rigidity ◽  
The Relationship ◽  
Current Systems

<div> <p>The correlations between variations in the geomagnetic cutoff rigidity of cosmic rays and the Dst and Kp geomagnetic indices and solar-wind and IMF parameters are calculated for the three phases of the magnetic storm of November 20–21, 2003: before the storm and during its main and recovery phases. The correlations are the strongest between variations in the cutoff rigidity and the Dst index during all stages. A significant correlation was recorded with the By component of IMF and the field magnitude B; the correlation with By dominated during the main phase, and the correlation with B was dominant during the recovery phase. There is also a high correlation with the dynamic parameters of solar activity during the main phase, especially with the solar-wind speed.</p> <div> <p>As far as we know, hysteresis phenomena have been discovered for the first time in the relationship between the cosmic-ray cutoff rigidities and the parameters of the helio- and magnetosphere on the scale of the magnetic storm (with Moscow station as an example). Loop-like patterns formed, because the trajectories of variations in the cutoff rigidities versus the studied parameters during storm intensification (development of current systems) did not coincide with the trajectories during the recovery phase (decay of current systems). The correlations of the cutoff rigidities with Dst and Kp indices were characterized by a narrow hysteresis loop, and their correlations with the IMF parameters were characterized by a wide hysteresis loop. The hysteresis loops for the relationship between the cutoff rigidities and solar-wind density and pressure were disordered.</p> </div> </div>

Does the duration of the magnetic storm recovery phase depend on the storm development rate in its main phase?

2015 ◽  
Vol 55 (4) ◽  
pp. 421-424 ◽  
Author(s):  
Yu. I. Yermolaev ◽  
I. G. Lodkina ◽  
N. S. Nikolaeva ◽  
M. Yu. Yermolaev
Keyword(s):  
Magnetic Storm ◽  
Recovery Phase ◽  
Development Rate ◽  
Main Phase

scholarly journals Magnetoencephalographic mapping of the language-specific cortex

1998 ◽  
Vol 5 (5) ◽  
pp. E2 ◽  
Author(s):  
Andrew C. Papanicolaou ◽  
Panagiotis G. Simos ◽  
Joshua I. Breier ◽  
George Zouridakis ◽  
L. James Willmore ◽  
...  
Keyword(s):  
Receptive Language ◽  
Cortical Stimulation ◽  
Hemispheric Dominance ◽  
Mapping Technique ◽  
Dominant Hemisphere ◽  
Language Mapping ◽  
Valuable Adjunct ◽  
Simple Language ◽  
Noninvasive Mapping ◽  
Further Development

Object In this paper the authors introduce a novel use of magnetoencephalography (MEG) for noninvasive mapping of language-specific cortex in individual patients and in healthy volunteers. Methods The authors describe a series of six experiments in which normative MEG data were collected and the reliability, validity, and topographical accuracy of the data were assessed in patients who had also undergone the Wada procedure or language mapping through intraoperative cortical stimulation. Conclusions Findings include: 1) receptive language-specific areas can be reliably activated by simple language tasks and this activation can be readily recorded in short MEG sessions; 2) MEG-derived maps of each individual are reliable because they remain stable over time and are independent of whether auditory or visual stimuli are used to activate the brain; and 3) these maps are also valid because they concur with results of the Wada procedure in assessing hemispheric dominance for language and with the results of cortical stimulation in identifying the precise topography of receptive language regions within the dominant hemisphere. Although the MEG mapping technique should be further refined, it has been shown to be efficacious by correctly identifying the language-dominant hemisphere and specific language-related regions within this hemisphere. Further development of the technique may render it a valuable adjunct for routine presurgical planning in many patients who harbor tumors or have epilepsy.

scholarly journals Radial diffusion modeling with empirical lifetimes: comparison with CRRES observations

2005 ◽  
Vol 23 (4) ◽  
pp. 1467-1471 ◽  
Author(s):  
Y. Y. Shprits ◽  
R. M. Thorne ◽  
G. D. Reeves ◽  
R. Friedel
Keyword(s):  
Diffusion Model ◽  
Radiation Effects ◽  
Outer Zone ◽  
Recovery Phase ◽  
Decay Rates ◽  
Radial Diffusion ◽  
Main Phase ◽  
Relativistic Electrons ◽  
Storm Main Phase ◽  
Order Of Magnitude

Abstract. A time dependent radial diffusion model is used to quantify the competing effects of inward radial diffusion and losses on the distribution of the outer zone relativistic electrons. The rate of radial diffusion is parameterized by Kp with the loss time as an adjustable parameter. Comparison with HEEF data taken over 500 Combined Release and Radiation Effects Satellite (CRRES) orbits indicates that 1-MeV electron lifetimes near the peak of the outer zone are less than a day during the storm main phase and few days under less disturbed conditions. These values are comparable to independent estimates of the storm time loss rate due to scattering by EMIC waves and chorus emission, and also provide an acceptable representation of electron decay rates following the storm time injection. Although our radial diffusion model, with data derived lifetimes, is able to simulate many features of the variability of outer zone fluxes and predicts fluxes within one order of magnitude accuracy for most of the storms and L values, it fails to reproduce the magnitude of flux changes and the gradual build up of fluxes observed during the recovery phase of many storms. To address these differences future modeling should include an additional local acceleration source and also attempt to simulate the pronounced loss of electrons during the main phase of certain storms.

scholarly journals RELATIONSHIP OF THE ASY-H INDEX WITH INTERPLANETARY MEDIUM PARAMETERS AND AURORAL ACTIVITY IN MAGNETIC STORM MAIN PHASES DURING CIR AND ICME EVENTS

2020 ◽  
Vol 6 (1) ◽  
pp. 43-50
Author(s):  
Roman Boroev ◽  
Mikhail Vasiliev
Keyword(s):  
Magnetic Storm ◽  
Interplanetary Medium ◽  
Magnetic Storms ◽  
Main Phase ◽  
Storm Main Phase ◽  
H Index ◽  
Auroral Activity ◽  
Different Types ◽  
Relationship Of ◽  
The Relationship

In this study, we examine the relationship of the ASY-H index characterizing the partial ring current intensity with interplanetary medium parameters and auroral activity during the main phase of magnetic storms, induced by the solar wind (SW) of different types. Over the period 1979–2017, 107 magnetic storms driven by CIR and ICME (MC + Ejecta) events have been selected. We consider magnetic storms with Dstmin≤ – 50 nT. The average ASY-H index (ASYaver) during the magnetic storm main phase is shown to increase with increasing SW electric field and southward IMF Bz regardless of SW type. There is no relationship between ASYaver and SW velocity. For the CIR and ICME events, the average AE (AEaver) and Kp (Kp aver) indices have been found to correlate with ASYaver. The highest correlation coefficient between AEaver and ASYaver (r = 0.74) is observed for the magnetic storms generated by CIR events. A closer relationship between Kp aver and ASYaver (r = 0.64) is observed for the magnetic storms induced by ICME events. The ASYaver variations correlate with Dstmin. The relationship between ASYaver and the rate of storm development is weak.

scholarly journals Another way of deriving the ring current decay time during disturbed periods

1995 ◽  
Vol 38 (2) ◽  
Author(s):  
M. M. Zossi de Artigas ◽  
J. R. Manzano
Keyword(s):  
Ring Current ◽  
Coupling Parameter ◽  
Life Time ◽  
Recovery Phase ◽  
Main Phase ◽  
Physical Analysis ◽  
Inner Magnetosphere ◽  
Current Decay ◽  
The Many ◽  
Energy Dissipated

Coupling parameter, E, and the total energy dissipated by the magnetosphere, UT, are determined for six disturbed periods, following three known criteria for UT computation. It is observed that UT exceeds E for Dst < -90 nT, for alI models. Differences between models reside on the estimated valnes for the particles' life time il1 the equatorial ring current. The values of TR, used in the models, are small during the main phase of the di."turbance, in disagreement with the charge exchange life time of the majority species, H+ and O'-. Based on this conclusion, a different criterion to calculate TR is proposed, differentiating the different stages of the perturbation. TR is calculated, for the main phase of the storm, from the rate of energy deposition estimation, Q, in the ring current. For Dst recovery phase, the vallles are obtained from a ring current decay law computation. The UTvu calculated, physically more coherent with the processes occurring during the event, is now smaller than expected. In this sense, it is understood that the power generated by the solar wind-magnetosphere dy- namo, should also be distributed in the inner magnetosphere, auroral zones and equatorial ring current, as in the outer magnetosphere, plasmoids in the tail shot in antisolar direction. A further adjustment of E, with the Chapman-Ferraro distance, 10' variable, has been made. Although the reslllts, improve the estimation of E, they are sti!l smaller than UT, except UTNU, for some disturbed periods. This result indicates the uncertainty in the computation of the input energy, by using the many expressions proposed in the literature, which are always presented as laws proportional to a given group of parameters, with an unknown factor of proportionality, which deserves more detailed physical analysis.

scholarly journals EFEK CME HALO PENUH PADA IONOSFER LINTANG RENDAH DARI DATA GPS BAKO DI CIBINONG [EFFECT OF FULL HALO CME ON LOW LATITUDE IONOSPHERE FROM BAKO GPS DATA IN CIBINONG]

2018 ◽  
Vol 15 (1) ◽  
pp. 51
Author(s):  
Fakhrizal Muttaqien ◽  
Buldan Muslim
Keyword(s):  
Total Electron Content ◽  
Geomagnetic Storm ◽  
Geomagnetic Disturbance ◽  
Main Phase ◽  
Gps Data ◽  
Electron Content ◽  
Ionospheric Storm ◽  
Total Electron ◽  
Dst Index ◽  
Software Analysis

A full halo coronal mass ejections (CMEs) are most energetic solar events that eject huge amount of mass and magnetic fields into heliosphere with 360o angular angle. The full halo CME effect on the ionosphere can be determined from the ionospheric total electron content (TEC) derived from GPS data. GPS data from BAKO station in Cibinong, satellite orbital data (brcd files) and intrumental bias data (DCB files) have been used to obtain TEC using GOPI software. Analysis of  the full halo CME data, Dst index, and TEC during October 2003 and February 2014 showed that the full halo CME could cause ionospheric disturbances called ionospheric storms. Magnitude and time delay of the ionospheric storms  depended on the full halo CME speed. For the high-speed full halo CME, the negative ionospheric storm generally occured during recovery phase of the geomagnetic storm. When the initial phase of geomagnetic disturbance with increasing Dst index more than +30 nT, the ionospheric storm occured during main phase of geomagnetic disturbance although the main phase of geomagnetic disturbance did not reach geomagnetic storm condition. ABSTRAKCoronal mass ejection  (CME) halo penuh merupakan peristiwa matahari  berenergi tinggi, yang menyemburkan massa dan medan magnet ke heliosfer dengan sudut angular sebesar 360º. Efek  CME halo penuh pada ionosfer dapat diketahui dari Total Electron Content (TEC). Data GPS BAKO di Cibinong, data orbit satelit (file brcd) dan data bias instrumental (file DCB) dapat digunakan untuk penentuan TEC menggunakan software GOPI. Analisis data CME halo penuh, indeks Dst, dan TEC selama bulan Oktober 2003 dan Februari 2014 menunjukkan bahwa CME halo penuh dapat menimbulkan gangguan ionosfer yang disebut badai ionosfer. Besar dan selang waktu badai ionosfer setelah terjadinya CME, tergantung pada kelajuan CME halo penuh. Untuk CME halo penuh berkelajuan tinggi, badai ionosfer negatif umumnya terjadi pada fase pemulihan badai geomagnet. Jika fase awal gangguan geomagnet diawali dengan peningkatan indeks Dst melebihi +30 nT, maka badai ionosfer dapat terjadi pada fase utama gangguan geomagnet walau gangguan geomagnet setelah  fase awal tidak mencapai kondisi badai geomagnet. 

scholarly journals The caspase-dependent apoptosis gradient in the testis of the blue shark, Prionace glauca

Reproduction ◽  
2013 ◽  
Vol 145 (3) ◽  
pp. 297-310 ◽  
Author(s):  
Leon M McClusky
Keyword(s):  
Sertoli Cell ◽  
Caspase 3 ◽  
Recovery Phase ◽  
Nuclear Antigen ◽  
Death Process ◽  
Type B ◽  
Blue Shark ◽  
Testicular Morphology ◽  
Further Development ◽  
Proliferating Cell

The severe degenerative phenomena that characterises spermatogenesis in mating blue sharks involves spatially separated germ cell and Sertoli cell apoptosis. Unlike that observed in multilayered type B spermatogonial and spermatocyte cysts caspase-3-dependent apoptosis of single and multinucleate type B spermatogonia in one to three spermatogonial layered cysts resulted in their complete fragmentation, delayed phagocytic removal and displacement of the apoptotic bodies towards the perilumenar Sertoli nuclei. Changes were observed in the immunostaining patterns of proliferating cell nuclear antigen (PCNA), including subtle changes in cytoplasmic and overall intense immunostaining, labelled single and multinucleate cell (MNC) apoptotic spermatogonial masses in premeiotic cysts in different stages of the protracted death process. Initial massive MNC formation at the mitosis–meiosis transition eventually left its imprint in the spermatogenic sequence in the form of vacuolated areas in the affected and subsequent stages. Some of the latter attempted further developmental advance but eventually degenerated. The observed higher PCNA index of spermatogonia in vacuolated testes compared to testes with the MNC type of degeneration indicated that the former testicular morphology represented, in essence, the recovery phase from the pronounced MNC death earlier. Events culminating in the eventual apoptotic demise of the Sertoli cells themselves included the abortion of further development (presumably due to a suboptimal Sertoli:germ cell ratio) of those germ cells left over from the wave of MNC death that swept the cysts. Eventually the Sertoli-cell-only cysts became apoptotic as they were engulfed by the infiltrating lymphomyeloid cells from the epigonal organ associated with the mature pole of the testis.

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