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1.
The structure of penetration of solar cosmic rays (SCRs) with energies of 1–100 MeV into the Earth’s magnetosphere before
a strong magnetic storm of October 29–31, 2003, is studied based on the CORONAS-F satellite data. The effect of north-south
asymmetry was observed in the polar caps for more than 12 h, which made it possible to study the dynamics of the boundary
between the polar cap (the magnetotail) and the auroral zone (the quasi-trapping region). A previously unknown effect of dropouts
in the SCR intensity latitudinal profile during the substorm active phases has been detected in the auroral magnetosphere.
The mechanism by which dropouts are formed owing to the local distortion of the magnetic field line configuration, resulting
in radial diffusion of particles from this region, has been proposed. 相似文献
2.
Based on the WIND and GOES satellite data on the solar wind and IMF parameters and the data on the surface magnetic field,
it has been indicated that the secondary MHD rarefaction wave can affect the geomagnetic field during a storm sudden commencement
(SSC) event. The secondary rarefaction wave originates in the magnetosheath when the shock wave interacts with the Earth’s
magnetosphere. 相似文献
3.
The event of March 12–19, 2009, when a moderately high-speed solar wind stream flew around the Earth’s magnetosphere and carried
millihertz ultralow-frequency (ULF) waves, has been analyzed. The stream caused a weak magnetic storm (D
st min = −28 nT). Since March 13, fluxes of energetic (up to relativistic) electrons started increasing in the magnetosphere. Comparison
of the spectra of ULF oscillations observed in the solar wind and magnetosphere and on the Earth’s surface indicated that
a stable common spectral peak was present at frequencies of 3–4 mHz. This fact is interpreted as evidence that waves penetrated
directly from the solar wind into the magnetosphere. Possible scenarios describing the participation of oscillations in the
acceleration of medium-energy (E > 0.6 MeV) and high-energy (E > 2.0 MeV) electrons in the radiation belt are discussed. Based on comparing the event with the moderate magnetic storm of
January 21–22, 2005, we concluded that favorable conditions for analyzing the interaction between the solar wind and the magnetosphere
are formed during a deep minimum of solar activity. 相似文献
4.
A. A. Karakhanyan G. A. Zherebtsov V. A. Kovalenko S. I. Molodykh 《Geomagnetism and Aeronomy》2011,51(8):1155-1159
The Earth’s crossings of the magnetic sector boundaries are accompanied by changes in the magnetosphere, ionosphere, and troposphere.
We considered the baric field’s response to the crossing of the inter-planetary magnetic field (IMF) sector boundaries during
a geomagnetically quiet period. The IMF sign is shown to affect atmospheric pressure in high-latitude regions. The efficiency
and sign of the relationship vary during the year. The baric field response to the Earth’s crossing of the IMF sector boundaries
is most distinct during equinoxes. It is shown that, during a geomagnetically quiet period, the circulation processes in the
atmosphere drive the changes in the atmospheric pressure when the Earth passes from one IMF sector into another. 相似文献
5.
Geomagnetism and Aeronomy - A geomagnetic storm is a major disturbance in the Earth’s magnetosphere due to the solar wind entering the magnetosphere and ionosphere, lasting about 1–3... 相似文献
6.
A new index of wave activity (ULF index) is applied to analyze daytime magnetic pulsations in the Pc5 range (f = 2–7 mHz) during ten successive recurrent magnetic storms (CIR (corotating interaction region) storms) of 2006. The most
intense daytime geomagnetic Pc5 pulsations on the Earth’s surface in all phases of CIR storms are predominantly observed in
the pre-noon sector at latitudes higher than 70°, while those in CME storms (storms initiated by coronal mass ejection (CME))
are observed at latitudes lower than 70°. A comparison of wave activity during CIR and CME storms has shown that the amplitude
of Pc5 pulsations in CIR storms is much smaller than that in CME storms and the spectrum maximum is observed at lower frequencies
and higher latitudes. At the same time, the mechanism of ULF wave generation during both types of magnetic storms seems to
be similar, namely, resonance of magnetic field lines due to the development of the Kelvin-Helmholtz instability caused by
an approach of a high-velocity solar wind stream to the Earth’s magnetosphere. Since resonance oscillations are excited only
in the closed magnetosphere, the higher-latitude position of the Pc5 pulsation intensity maximum in CIR storms points to larger
dimensions of the daytime magnetosphere during CIR storms as compared to CME storms. 相似文献
7.
Disturbances in the magnetic field and magnetospheric and ionospheric plasma registered on December 14–16, 2006, during a
strong magnetic storm caused by a solar flare of 4B/X3.4 class are studied. It is shown that in the north of Yakutia, interactions between the Earth’s magnetosphere and the region
of high dynamic pressure of the solar wind led to the formation of sporadic layers in the ionospheric E and F regions, depletion of the critical frequency of the F2 layer, and total absorption. At the end of the magnetic storm’s main phase, anomalously high values of foF2 exceeding the quiet level by a factor of 1.5–1.7 were detected. It was found that the disturbances detected by ground-based
observatories had developed on the background of changes in the temperature, density, and the pitch-angle distribution of
particles at the geostationary orbit manifesting radial shifts of magnetospheric structures (magnetopause, cusp/cleft, and
plasma sheet) relative to the observation points. A conclusion is drawn that in this case, changes in the near-Earth plasma
and magnetic field manifest the dynamics of the physical conditions at the magnetospheric boundary and diurnal rotation of
the Earth. 相似文献
8.
V. V. Kalegaev 《Geomagnetism and Aeronomy》2011,51(7):855-865
A review of modern dynamic models of the Earth’s magnetosphere (the A2000 paraboloid model and Tsyganenko’s T01 model) is
presented. For the magnetic storm of January 9–11, 1997, the results of joint calculations of the magnetospheric magnetic
field are presented and contributions of the large-scale magnetospheric currents to the D
st variations are analyzed. Both models were shown to be well consistent with measurement data; the contribution of the magnetotail
current system to D
st is comparable to the contribution of the ring current. At the same time, the relative dynamics of magnetospheric current
systems are different in different models. The differences in the magnetic field variation profiles for various current systems
calculated by the A2000 and T01 models are explained by model parameterizations. 相似文献
9.
L. V. Kozak S. P. Savin V. P. Budaev V. A. Pilipenko L. A. Lezhen 《Geomagnetism and Aeronomy》2012,52(4):445-455
The statistical features of the magnetic field and ion flux fluctuations in the boundary regions of the Earth’s magnetosphere have been studied on different timescales based on the Interball satellite measurements. Changes in the form and parameters of the probability density function have been studied for the periods when the satellite was in the solar wind plasma, different magnetosheath regions, and the turbulent boundary layer (TBL) at the polar cusp outer boundary. Variations in the probability density function maximum (P 0) and the kurtosis value as characteristics of the turbulence property evolution on different timescales have been studied. Two asymptotic regimes of P 0, which are characterized by different power laws, have been found. The structural functions of different orders and the types of diffusion processes in different regions, depending on time variations in the generalized diffusion coefficient, have been studied in order to analyze the character of diffusion processes. For the magnetosheath regions, TBL, and polar cusp, it has been found that the diffusion coefficient increases in the course of time (i.e., the regime of superdiffusion has been obtained). In the foreshock region before the main shock, turbulent processes are described by the Kolmogorov model of classical diffusion. 相似文献
10.
A. A. Vazhenin 《Geomagnetism and Aeronomy》2010,50(2):225-230
The molecular oxygen concentration at altitudes of 90–120 km has been estimated, using the CORONAS-F/VUSS-L data on the extreme
UV absorption in the Earth’s atmosphere. It has been indicated that the concentration at these altitudes is a factor of 1.3
as high as the concentration according to the Jacchia-77 model. It has been revealed that the level of solar activity slightly
affects the molecular oxygen concentration at these altitudes. 相似文献
11.
O. V. Kozyreva I. N. Myagkova E. E. Antonova N. G. Kleimenova 《Geomagnetism and Aeronomy》2009,49(6):741-749
Precipitation of electrons with energies of 0.3–1.5 MeV has been analyzed based on the CORONAL-F satellite data at polar latitudes
of the Northern Hemisphere on December 13, 2003. The instants of electron precipitation have been compared with the ground-based
observations of geomagnetic disturbances and auroras near the satellite orbit projection. It has been indicated that precipitation
of energetic electrons in the high-latitude nightside sector is accompanied by the simultaneous development of bay-like magnetic
field disturbances on the Earth’s surface and the appearance of riometer absorption bursts and Pi3 geomagnetic pulsations,
and auroras. 相似文献
12.
S. I. Boldyrev O. P. Kolomytsev G. S. Ivanov-Kholodny A. P. Ignatyev 《Geomagnetism and Aeronomy》2009,49(8):1278-1282
The present-day models of the Earth’s upper atmosphere make it possible to construct the spatial-temporal pattern of variations
in the atmospheric parameters on the planetary scale in essence in the averaged form. The set of data on the satellite deceleration
in the atmosphere, probe measurements aboard geophysical rockets, and radiowave incoherent scatter measurements in the Earth’s
atmosphere are used to construct these standard models. The current level of the space studies makes it possible to use a
new method to study the Earth’s upper atmosphere: to study the upper atmosphere by measuring the absorption of the solar XUV
radiation by the Earth’s atmosphere during the solar disk observations. 相似文献
13.
The structure and physical conditions in 104 coronal mass ejections (CMEs) with a clear-cut leading shock front have been
considered using satellite data for 1996–2008. In 99% of cases, the action of increased shock front dynamic pressure on the
Earth’s magnetosphere resulted in the origination of geomagnetic storms with sudden commencement. 相似文献
14.
Experimental proofs of the existence of the formation and destruction mechanisms of solar proton belts in the inner magnetosphere at a rapid change in the penetration boundary of solar protons are presented. An analysis of the measurements of solar protons and alpha-particles on board the Coronas-F low-altitude polar satellite during the magnetic storms in October–November 2003 is performed. During this period, formation and destruction of the belts of solar cosmic rays was observed several times. The compression of the magnetosphere during a storm makes possible the direct penetration of solar protons deep into the inner magnetosphere. The proton trajectories outside the penetration boundary are open, and the preliminary captured particles can easily leave the magnetosphere. During the recovery of the magnetospheric configuration, when the penetration boundary goes away from the Earth, the solar protons and alpha-particles with relatively low velocity of the magnetic drift remain stably captured, whereas the particles of higher energies follow the motion of the penetration boundary. That is why the energy range of the captured protons is limited from above in contrast to the effect of injection during ineffective SC in the low-energy region. 相似文献
15.
N. A. Zolotukhina 《Geomagnetism and Aeronomy》2010,50(8):963-969
A comparative analysis of extremely low frequency waves registered by Cluster satellites after a sudden impulse (SI) and the
following substorm onset (SO) at distances L ∼ 4 from the Earth’s center was performed. It was shown that both phenomena in the equatorial morning magnetosphere activated
magnetic field oscillations of periods from 40 to 200 s. Oscillations accompanying SI and SO were found to be of similar spectral
composition but different polarizations. The differences in polarization became well-pronounced near the main spectral maximum
(100–130 s), where the transition from SI to SO was accompanied by reverse of rotation of the magnetic field disturbance vector
and by reorientation of the oscillation polarization ellipse. 相似文献
16.
The possibility that conditions on the Sun and in the Earth’s magnetosphere can affect human health at the Earth’s surface has been debated for many decades. This work reviews the research undertaken in the field of heliobiology, focusing on the effect of variations of geomagnetic activity on human cardiovascular health. Data from previous research are analysed for their statistical significance, resulting in support for some studies and the undermining of others. Three conclusions are that geomagnetic effects are more pronounced at higher magnetic latitudes, that extremely high as well as extremely low values of geomagnetic activity seem to have adverse health effects and that a subset of the population (10–15%) is predisposed to adverse health due to geomagnetic variations. The reported health effects of anthropogenic sources of electric and magnetic fields are also briefly discussed, as research performed in this area could help to explain the results from studies into natural electric and magnetic field interactions with the human body.Possible mechanisms by which variations in solar and geophysical parameters could affect human health are discussed and the most likely candidates investigated further. Direct effects of natural ELF electric and magnetic fields appear implausible; a mechanism involving some form of resonant absorption is more likely. The idea that the Schumann resonance signals could be the global environmental signal absorbed by the human body, thereby linking geomagnetic activity and human health is investigated. Suppression of melatonin secreted by the pineal gland, possibly via desynchronised biological rhythms, appears to be a promising contender linking geomagnetic activity and human health. There are indications that calcium ions in cells could play a role in one or more mechanisms. It is found to be unlikely that a single mechanism can explain all of the reported phenomena. 相似文献
17.
Alexander Z. Bochev Karel Kudela Iren A. Dimitrova Petko Nenovski Ashwini K. Sinha Marián Slivka 《Studia Geophysica et Geodaetica》2009,53(4):537-556
Examples of long period Pc5 magnetic field pulsations near field-aligned current (FAC) regions in the high-latitude magnetosphere,
observed by INTERBALL-Auroral satellite during January 11, April 11 and June 28, 1997 are shown. Identification of corresponding
magnetosphere regions and subregions is provided by electrons and protons in the energy-range of 0.01–100 keV measured simultaneously
onboard the spacecraft. The examined Pc5 pulsations reveal a compressional character. A fairly good correlation is demonstrated
between these ULF Pc5 waves and the consecutive injection of magnetosheath low energy protons. The ULF Pc5 wave occurrence
is observed in both upward and downward FACs. 相似文献
18.
Magnetic Pulsations: Their Sources and Relation
to Solar Wind and Geomagnetic Activity 总被引:1,自引:1,他引:0
Ultra low frequency (ULF) waves incident on the Earth are produced by processes in the magnetosphere and solar wind. These
processes produce a wide variety of ULF hydromagnetic wave types that are classified on the ground as either Pi or Pc pulsations
(irregular or continuous). Waves of different frequencies and polarizations originate in different regions of the magnetosphere.
The location of the projections of these regions onto the Earth depends on the solar wind dynamic pressure and magnetic field.
The occurrence of various waves also depends on conditions in the solar wind and in the magnetosphere. Changes in orientation
of the interplanetary magnetic field or an increase in solar wind velocity can have dramatic effects on the type of waves
seen at a particular location on the Earth. Similarly, the occurrence of a magnetospheric substorm or magnetic storm will
affect which waves are seen. The magnetosphere is a resonant cavity and waveguide for waves that either originate within or
propagate through the system. These cavities respond to broadband sources by resonating at discrete frequencies. These cavity
modes couple to field line resonances that drive currents in the ionosphere. These currents reradiate the energy as electromagnetic
waves that propagate to the ground. Because these ionospheric currents are localized in latitude there are very rapid variations
in wave phase at the Earth’s surface. Thus it is almost never correct to assume that plane ULF waves are incident on the Earth
from outer space. The properties of ULF waves seen at the ground contain information about the processes that generate them
and the regions through which they have propagated. The properties also depend on the conductivity of the Earth underneath
the observer. Information about the state of the solar wind and the magnetosphere distributed by the NOAA Space Disturbance
Forecast Center can be used to help predict when certain types and frequencies of waves will be observed. The study of ULF
waves is a very active field of space research and much has yet to be learned about the processes that generate these waves. 相似文献
19.
The ring current is conventionally considered responsible for the shift of the boundary of solar proton penetration into the inner Earth’s magnetosphere during magnetic storms. The cases of a boundary shift were observed in some works on the dark side before the onset of a magnetic storm, i.e., at positive values of the Dst index. In this work, this type of shift of the penetration boundary is considered in detail with two storms as examples. It is shown that the corresponding distortion of the magnetosphere configuration is induced by an increase in the solar wind pressure during the initial phase of a magnetic storm. The current induced in this case on the magnetopause is closed by a current in the equator plane, which changes the configuration of the dark side of the inner magnetosphere, weakens the magnetic field, and allows solar protons to penetrate the inner magnetosphere. The significant difference in the positions of the penetration boundary and the boundary found from models of the magnetosphere magnetic field can be explained by insufficient consideration of closing currents. 相似文献
20.
We confirm the close synoptic relationship of the sectoral structure of the Sun’s magnetic field of the with the near-Earth
tropospheric pressure with a case study of three European points (Troitsk, Rome, Jungfrau) in the period of the anomalously
hot summer of June–August 2010. We substantiate the position that such a relationship was fostered by the anomalously low
solar activity as a result of superposition of the minima of the 22- and 180-year cycles. Sectoral analysis of the solar-tropospheric
relationships has shown that the appearance of a blocking anticyclone in the Moscow suburbs, its expansion to Rome and Jungfrau,
and subsequent retreat at first from these points, and then from the Moscow suburbs was closely related to solar activity
phenomena producing, according to contemporary notions, cyclonic activity, shown by simulation of the Earth’s electric field. 相似文献