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1.
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
2.
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
3.
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
4.
N. G. Kleimenova O. V. Kozyreva J. Manninen T. Raita T. A. Kornilova I. A. Kornilov 《Geomagnetism and Aeronomy》2011,51(6):730-740
A complex of geophysical phenomena (geomagnetic pulsations in different frequency ranges, VLF emissions, riometer absorption,
and auroras) during the initial phase of a small recurrent magnetic storm that occurred on February 27–March 2, 2008, at a
solar activity minimum has been analyzed. The difference between this storm and other typical magnetic storms consisted in
that its initial phase developed under a prolonged period of negative IMF B
z
values, and the most intense wave-like disturbances during the storm initial phase were observed in the dusk and nighttime
magnetospheric sectors rather than in the daytime sector as is observed in the majority of cases. The passage of a dense transient
(with N
p
reaching 30 cm−3) in the solar wind under the southward IMF in the sheath region of the high-speed solar wind stream responsible for the discussed
storm caused a great (the AE index is ∼1250 nT) magnetospheric substorm. The appearance of VLF chorus, accompanied by riometer absorption bursts and Pc5
pulsations, in a very long longitudinal interval of auroral latitudes (L ∼ 5) from premidnight to dawn MLT hours has been detected. It has been concluded that a sharp increase in the solar wind
dynamic pressure under prolonged negative values of IMF B
z
resulted in the global (in longitude) development of electron cyclotron instability in the Earth’s magnetosphere. 相似文献
5.
Measurements of solar cosmic ray (SCR) protons in the magnetosphere can be used to verify models of the Earth’s magnetic field.
The latitudinal profiles of precipitating SCRs with energies of 1–90 MeV were measured on the CORONAS-F low-orbiting satellite
during a strong magnetic storm on October 29–30, 2003. A flux of precipitating protons can remain equal to the interplanetary
flux only due to a strong pitch angle diffusion that originates when the radius of the field line curvature is close to that
of the particle rotation Larmor radius. The observed boundaries of the strong diffusion region can be compared with the boundaries
anticipated according to the models of the magnetic field of the Earth’s magnetosphere. The adiabaticity parameter values,
calculated for several instants of the CORONAS-F satellite pass based on the TS05 and parabolic models, do not always correspond
to measurements. How possible changes in the model configurations of the magnetic field can allow us to eliminate discrepancies
with the experiment and to explain why solar protons with energies of several megaelectronvolts penetrate deep in the Earth’s
inner magnetosphere is considered here. 相似文献
6.
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
7.
The excitation of long-period irregular pulsations in the 2.0–6.0 mHz range (ipcl pulsation series) in the Earth’s magnetosphere, depending on the set of solar wind plasma and IMF parameters, has been studied experimentally. It has been found that burst regimes are observed when the solar wind dynamic pressure and velocity are higher than V ∼ 320 km/s and P ∼ 1 nPa, respectively. It has been indicated that the dynamics of the ipcl pulsation intensity and fractal structure largely depend on the solar wind plasma velocity and magnetic pressure, respectively. An analysis of the relationship between the appearance of ipcl pulsation burst series and large-scale solar wind streams and polar coronal holes made it possible to identify solar geoeffective regions, which can cause solar wind streams and Alfvén waves that promote the generation of burst regimes. On the basis of the studied conditions of the interplanetary medium, favourable for the excitation of ipcl pulsation burst series, and generalization of morphological patterns, the possible mechanisms of their generation have been considerded. It has been demonstrated that ipcl burst regimes are most probably generated as wind instability in hydrodynamics (the Miles-Phillips mechanism). The Miles-Phillips instability is related to different factors in the solar wind stream, among which turbulence, the threshold velocity value, and pressure fluctuations play a defining role. Precisely these regularities are typical of the ipcl burst regime generation conditions. 相似文献
8.
The paper suggests that spacecraft equipment failures in the near-Earth environment may be caused by one of the following
types of streams coming to the Earth’s orbit: (a) slow solar wind in the streamer belt or chains; (b) sporadic solar wind;
(c) proton flux with an energy of E > 60 MeV. The laws of solar-terrestrial physics derived to date allow sufficiently reliable determination of the sources
of these streams on the Sun as well as fairly precise calculation of their parameters and time of arrival at the Earth’s orbit.
We have concluded that spacecraft maintenance and extension of their service life require timely and fairly accurate information
regarding the onset of an adverse environmental effect on spacecraft. A successful solution to the problem depends mainly
on the current state of the art of research and development in solar-terrestrial, ionospheric, and magnetospheric physics. 相似文献
9.
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
10.
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
11.
S. N. Sokolov 《Geomagnetism and Aeronomy》2011,51(6):741-752
During magnetic storms (MS’s) in the ionospheric D region, changes in the electron density and corresponding effects on radiowave propagation are observed. The differences
in manifestations of MS’s in the lower ionosphere are mainly caused by the time and spatial differences in precipitations
of energetic electrons. It is shown that the observed differences in the effects of storms in the D region are related to the differences in the corresponding types of MS’s determined by the observed fluxes of energetic electrons
(E ∼ 0.1–2 MeV) at L ≈ 3–8. The storm types are identified by changes in the geomagnetic ap and AE indices and the ap/Dst and AE/Dst ratios during the recovery phase of a storm. 相似文献
12.
《Journal of Atmospheric and Solar》2008,70(14):1774-1788
We investigated the role of whistler-mode chorus in accelerating outer radiation belt electrons during four moderate geomagnetic storms when data from the Polar Plasma Wave Investigation (PWI) were available. The storm time periods we examined included two storms associated with coronal mass ejections (CMEs), the well-studied January 10–13, 1997 International Solar Terrestrial Physics event and the May 12–15, 1997 event. We compared these two storms with two geomagnetically active periods that were not associated with CMEs. Although strong chorus emissions were observed during all four events, the association of electron acceleration with chorus emissions is not clear. During all four events, the Polar Comprehensive Energetic Particle and Pitch Angle Distribution (CEPPAD) experiment observed increases in the fluxes of energetic electrons (0.8<E<6.4 MeV). The two events associated with CMEs featured a sudden increase in the electron fluxes above 0.8 MeV that may have been related to the impact of the CME shock wave upon the magnetosphere. The other two events featured more gradual increases in the electron fluxes over a period of several days. The data from these events indicate that the role played by resonant interactions with chorus in accelerating electrons may depend on the upstream solar wind conditions driving the storm. 相似文献
13.
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
14.
V. I. Degtyarev S. E. Chudnenko I. P. Kharchenko B. Tsegmed B. Xue 《Geomagnetism and Aeronomy》2009,49(8):1208-1217
The relation of the maximal daily average values of the relativistic electron fluxes with an energy higher than 2 MeV, obtained
from the measurements on GOES geostationary satellites, during the recovery phase of magnetic storms to the solar wind parameters
and magnetospheric activity indices has been considered. The parameters of Pc5 and Pi1 geomagnetic pulsations and the relativistic
electron fluxes during the prestorm period and the main phase of magnetic storms have been used together with the traditional
indices of geomagnetic activity (A
E, K
p, D
st). A simple model for predicting relativistic electron fluxes has been proposed for the first three days of the magnetic storm
recovery phase. The predicted fluxes of the outer radiation belt relativistic electrons well correlate with the observed values
(R ∼ 0.8–0.9). 相似文献
15.
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
16.
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
17.
M. I. Verigin G. A. Kotova V. V. Bezrukikh G. N. Zastenker N. Nikolaeva 《Geomagnetism and Aeronomy》2009,49(8):1176-1181
Based on the magnetopause observations near the Earth by the Prognoz/Interball satellites in 1972–2000, the empirical model
of this boundary has been proposed, and the magnetopause behavior at different parameters of the oncoming solar wind has been
studied. For the first time, it has been detected that the Earth’s magnetopause is compressed by ∼5% in the direction perpendicular
to the plane including the vectors of the solar wind velocity and IMF. At the same time, any dependence of the subsolar magnetopause
position on the IMF B
z
component has not been revealed in the Progrnoz/Interball data. The proposed magnetopause model can be used to model the
position and shape of the near-Earth bow shock. 相似文献
18.
The characteristics of dayside auroras during the large (16–24 nT) positive values of the IMF B
z
component, observed on January 14, 1988, during the interaction between the Earth’s magnetosphere and the body of the interplanetary
magnetic cloud, have been studied based on the optical observations on Heiss Island. A wide band of diffuse red luminosity
with an intensity of 1–2 kilorayleigh (kR) was observed during 6 h in the interval 1030–1630 MLT at latitudes higher than
75° CGL. Rayed auroral arcs, the brightness of which in the 557.7 nm emission sharply increased to 3–7 kR in the postnoon
sector immediately after the polarity reversal of the IMF B
y
component from positive to negative, were continuously registered within the band. Bright auroral arcs were observed at the
equatorward edge of red luminosity. It has been found out that the red auroral intensity increases and the band equatorward
boundary shifts to lower latitudes with increasing solar wind dynamic pressure. However, a direct proportional dependence
of the variations in the auroral features on the dynamic pressure variations has not been found. It has been concluded that
the source of bright discrete auroras is located in the region of the low-latitude boundary layer (LLBL) on closed geomagnetic
field lines. The estimated LLBL thickness is ∼3 R
e
. It has been concluded that the intensity of the dayside red band depends on the solar wind plasma density, whereas the position
of the position equatorward boundary depends on the dynamic pressure value and its variations. 相似文献
19.
The relation of the fluxes of relativistic electrons in geostationary orbit during magnetic storms to the state of the magnetosphere and variations in the solar wind parameters is studied based on the GOES satellite data (1996–2000). It has been established that, in ～52–65% of all storms, the fluxes of electrons with energies higher than 0.6 and 2 MeV during the storm recovery phase are more than twice as high as the electron fluxes before a storm. It has been indicated that the probability of such cases is closely related to the prestorm level of fluxes and to a decrease in fluxes during the storm main phase. It has been found that the solar wind velocity on the day of the storm main phase and the geomagnetic activity indices at the beginning of the storm recovery phase are also among the best indicators of occurrence of storms with increased fluxes at the storm recovery phase. 相似文献
20.
Karavaev Yu. A. Sapronova L. A. Bazarzhapov A. D. Saifudinova T. I. Kuz’minykh Yu. V. 《Geomagnetism and Aeronomy》2009,49(7):961-969
The magnetospheric storm on November 20, 2003 was one of two greatest events in 1957–2003. The D
st* index reached −472 nT, the polar cap potential drop exceeded 200 kV, the polar cap boundary expanded up to Φ = 60°, the plasma
layer density in the synchronous orbit reached 5 cm−3, and the inner edge of the plasma sheet penetrated up to L ∼ 1.5R
E. The sequence of disturbance modes including some previously unknown is described. The distribution of the total power input
into the magnetosphere between the ionosphere (power Q
i) and the ring current (Q
DR), as well as the relative roles of the spontaneous substorms and the driven disturbances in the creation of the DR current, is analyzed. The values of the parameter α = Q
DR/Q
i are calculated with a step of 5 min. It is shown that intervals with α ≪ 1 and with maximums α ≫ 1 were observed in the events
under consideration. These results contradict the dominant opinion that the energy input into the magnetosphere during disturbances
is primarily dissipated in the ionosphere. The two types of α maximums are observed: one in the mode of a prevailing spontaneous
substorm and the other in the mixed mode of the substorm and driven disturbance. It is concluded that both types of the maximums
and corresponding enhancements of the DR current appeared due to the plasma turbulization processes in the substorm current
wedge. The parameter α appears to slowly increase from α ≪ 1 to α > 1 with increasing activity level; this trend supports
the driven model of creating the DR current due to an increase in the electric field of the solar wind. 相似文献