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1.
An experiment to measure energetic neutrons and gamma rays in space was launched in the first Indian scientific satellite,Aryobhata, on April 19, 1975. From this experiment, the first measurements in space of the Earth’s albedo fiux of neutrons of energy
between 20 and 500 MeV have been made; the values obtained for two mean geomagnetic vertical cut-off rigidities of 5.6 and
17.0 GV are (6.3±0.4)×10−2 and (1.4±0.3)×10−2 neutrons cm−2 sec−1 respectively. These measurements confirm that protons arising from cosmic ray albedo neutron decay, can adequately account
for the protons in the inner radiation belt. Observations on gamma rays of energy between 0.2 and 24 MeV have enabled the
determination of the total background gamma ray flux in space as a function of latitude. This in turn has permitted useful
information on the diffuse cosmic gamma rays. We have also observed four events that showed sudden increases in the gamma
ray counting rates between 0.2 and 4.0 MeV. Observational details of these events are given. 相似文献
2.
S. N. Kuznetsov B. Y. Yushkov J. Kaššovicová K. Kudela R. Bučík 《Czechoslovak Journal of Physics》2006,56(6):629-639
We report increases of cosmic-ray intensity at lowL shells, on the ground as well as on the altitude of 500 km, during the selected intervals when magnetosphere was strongly
disturbed. The geomagnetic transmissivity for cosmic ray vertical access has been computed for four events, using two geomagnetic
field models. The first event, namely, dated November 20–22, 2003, led to an increase of galactic cosmic-ray intensity due
to the improvement of magnetospheric transmissivity at neutron monitors with high nominal cut-off rigidity. Other two events
with high-energy solar proton emissions, namely, dated October 28 and November 2, 2003, caused different responses at middle
latitudes. The first one followed by the strong geomagnetic disturbance led to the shift of the penetration boundary of protons,
having(50–90) MeV at CORONAS-F satellite toL<3, coinciding approximately with the cut-off reduction expected byDst depression, while the other one, without remarkableDst decrease, did not shift the outer boundary of penetration belowL ≈ 4. And the fourth of the events, on November 8, 2004, with strong geomagnetic disturbance, yielded a complicated structure
of cosmic-ray time profiles: superimposed on the cosmic-ray decrease, viewed by neutron monitors and by CORONAS-F at high
latitude; an increase of intensity at middle latitudes both on the ground and on the altitude of 500 km has been observed
during theDst depression.
This work was supported by the Slovak Research and Development Agency under the contract No. APVV-51-053805. The work at Technical
University was supported by VEGA grant 2/4064. 相似文献
3.
D. P. Bhattacharyya 《Zeitschrift für Physik A Hadrons and Nuclei》1970,234(1):17-22
The vertical momentum spectrum of cosmic-ray muons has been determined by a counter controlled neon-hodoscope in the spectral region (0.2–3) Bev/c at geomagnetic latitude 12 °N. The observed spectrum agrees satisfactorily with the calculated spectrum of Olbert for muon momentum above 1.8 Bev/c. Below about 1.8 Bev/c, the measured spectrum exceeds slightly the theoretical spectrum of Olbert, calculated for the same geomagnetic latitude. The measured spectrum agrees with the experimental spectrum of Allkofer at 9 °N, but is somewhat below the spectrum obtained by Hayman in the low momentum region at 57.5 °N. This shows that there exists a latitude dependence of the low momentum muon spectrum. The estimated integral intensity of muon of momentum ≧320 Mev/c is found to be 7.3×10?3 cm?2 sec?1 str?1 which agrees with the value of other investigators1–9. 相似文献
4.
A. V. Uryson 《Journal of Experimental and Theoretical Physics》1998,86(1):6-10
The complicated shape of the cosmic ray spectrum recorded by giant arrays in the energy range 1017–1020 eV is analyzed. It is shown that in the energy region ∼1018–1019 eV the spectrum probably coincides with the injection spectrum whose exponent is equal approximately to 3.2–3.3. The flatter
component in the energy region (3.2–5.0)×1019 eV is due to braking of extragalactic protons on primordial photons (the cosmic background radiation). At energies exceeding
3.2×1019 eV the spectrum does not have a blackbody cutoff. The possibility of determining the distances at which cosmic rays originate
and investigating the evolution of their sources on the basis of ultrahigh-energy cosmic ray data is discussed.
Zh. éksp. Teor. Fiz. 113, 12–20 (January 1998) 相似文献
5.
We further present a three-dimensional (3D) ray-tracing study on the propagation characteristic of the superluminous R-X mode waves during high geomagnetic activity following our recent two-dimensional results [J. Geophys. Res. 112(2007)A10214]. We perform numerical calculations for this mode which originates at specific altitude r=2.0RE in the source cavity along a 70° night geomagnetic field line. We demonstrate that the ray path of the R-X mode is essentially governed by the azimuthal angle of the wave vector k. Ray paths starting with azimuthal angle 180° (or in the meridian plane) can reach the lowest latitude, but stay at relatively higher latitudes with the azimuthal angles other than 180° (or off the meridian plane). The results further supports the previous finding that the R-X mode may be physicallypresent in the radiation belts under appropriate conditions. 相似文献
6.
E. Keppler M. Fr?nz M. K. Reuss J. B. Blake R. Seidel J. J. Quenby 《Il Nuovo Cimento C》1996,19(6):915-920
Summary Measurements with the EPAC energetic-charged-particle instrument aboard Ulysses show between −15° and −65° ions and, to some
extent, also electrons apparently accelerated by shocks associated with a cororating interaction region (CIR) operating at
low latitudes. Particles could have reached Ulysses along magnetic-field lines which connect to the shocks in the more distant
heliosphere. Such connections evidently do not exist above −65°. Between the recurrent streams we find the underlying composition
to be similar to that of the anomalous component of cosmic rays (ACR). One channel (ELH), sensitive also to high-energy protons
(E>210 MeV), shows that, superimposed to the large-scale heliospheric modulation of galactic ions, a 26-day variation of the
flux is observed. Such modulation is also observed for the ACR, in phase with the galactic particle modulation, but anticorrelated
to the CIR-related low-energy particles. An estimate of the latitudinal and radial gradients of the galactic cosmic rays at
1 GV gives +0.4%/degree and −11%/AU, respectively.
Paper presented at the Special Session on the Ulysses mission of the XXIV International Cosmic-Ray Conference, Rome, August
28–September 8, 1995. 相似文献
7.
V. M. Dvornikov M. V. Kravtsova V. E. Sdobnov 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(3):370-374
According to the ground-based measurements of cosmic ray intensity on the worldwide network of stations and GOES spacecrafts, variations in cut-off rigidity in Irkutsk for the period 2004–2005 have been calculated. The calculated variations in cut-off rigidity are presented along with the Dst variations of the geomagnetic field. 相似文献
8.
An emulsion chamber was used to study the characteristics of high energy nuclear interactions from the production spectra
ofγ-rays. The emulsion chamber, which comprised of two parts, namely the detector and the graphite producer unit, was exposed
to cosmic rays for about 7 hr at an atmospheric depth of 10 g cm−2 at Hyderabad (geomagnetic latitude 7·6°N). 720 electromagnetic cascades due toγ-rays were recorded in the detector. These cascades were classified into three groups; (a)γ-rays from nuclear interactions in the detector (b)γ-rays from nuclear interactions in the producer unit and (c)γ-rays of atmospheric origin. The energies of the cascades were determined using photometric method. The spectra ofγ-rays from groups (a) and (c) were determined and compared with similar spectra obtained at greater atmospheric depths. The
spectra were found to obey a power law. The spectrum ofγ-rays of atmospheric origin was found to steepen at high energies,E
r>2200 GeV. 相似文献
9.
D. S. V. V. D. Prasad S. N. V. S. Prasad J. Vara Prasad N. S. M. P. Latha Devi P. V. S. Rama Rao 《Indian Journal of Physics》2010,84(4):345-358
Using the simultaneous data of ionosonde from a low latitude station, Waltair, India (17.7°N,83.3°E) in the Indian sector
and a mid latitude station, Kokubunji, Japan (35.7°N,139.5°E) in the Japanese sector during the high sunspot year of 2001,
a comparative study of the variations in the diurnal, seasonal and day to day characteristics of the ionospheric F-region
parameters, such as the virtual height of the F-layer (h’F) and the critical frequency of the F2 layer (foF2), are studied. The effect of geomagnetic activity variations of the F-region parameters over the low and mid
latitude stations is also presented. 相似文献
10.
O. V. Zolotov B. E. Prokhorov A. A. Namgaladze O. V. Martynenko 《Russian Journal of Physical Chemistry B, Focus on Physics》2011,5(3):435-438
The morphological features in the deviations of the total electron content (TEC) of the ionosphere from the background undisturbed
state as possible precursors of the earthquake of January 12, 2010 (21:53 UT (16:53 LT), 18.46° N, 72.5° W, 7.0 M) in Haiti
are analyzed. To identify these features, global and regional differential TEC maps based on global 2-h TEC maps provided
by NASA in the IONEX format were plotted. For the considered earthquake, long-lived disturbances, presumably of seismic origin,
were localized in the near-epicenter area and were accompanied by similar effects in the magnetoconjugate region. Both decreases
and increases in the local TEC over the period from 22 UT of January 10 to 08 UT of January 12, 2010 were observed. The horizontal
dimensions of the anomalies were ∼40° in longitude and ∼20° in latitude, with the magnitude of TEC disturbances reaching ∼40%
relative to the background near the epicenter and more than 50% in the magnetoconjugate area. No significant geomagnetic disturbances
within January 1–12, 2010 were observed, i.e., the detected TEC anomalies were manifestations of interplay between processes
in the lithosphere-atmosphere-ionosphere system. 相似文献
11.
A. V. Glushkov 《Journal of Experimental and Theoretical Physics》2010,111(1):57-63
The arrival directions of primary cosmic ray particles with energies E
0 ≥ 1017 eV and zenith angles θ ≤ 60° recorded on the Yakutsk array over the period 1974–2009 are analyzed. These events are shown
to have different anisotropies in different energy ranges. 相似文献
12.
通过大功率极低频(ELF)/甚低频(VLF)高频调幅波能有效地扰动低电离层电流, 形成等效的ELF/VLF电离层虚拟天线,辐射ELF/VLF波, 所辐射出的低频信号能够传播进入到磁层,对其传播特性的研究对于理解辐射带高能电子沉降具有重要意义.本文基于磁层射线追踪理论,通过数值模拟得到在低纬地区所激发出的ELF波在磁层中的射线路径,并对其特征进行分析.数值模拟结果表明, 从低纬激发的ELF波在南北半球来回弹跳,并逐渐传播到更远处,对于不同频率的ELF波, 频率越高,传播距离越近,频率越低,传播距离越远,在传播过程中, ELF波会逐渐倾向于在一个固定的磁层区域附近来回反射,在此过程中波法向角也逐渐变为90°,射线方向倾向于沿着背景磁场方向传播. 相似文献
13.
A. V. Glushkov 《Journal of Experimental and Theoretical Physics》2009,109(5):770-774
The arrival directions of primary cosmic ray particles with energies E
0 ≥ 1019 eV and zenith angles θ ≤ 60° recorded on the Yakutsk array over the period 1974–2009 are analyzed. These events separated
by different time intervals are shown to have different global anisotropies. 相似文献
14.
Hoover S Nam J Gorham PW Grashorn E Allison P Barwick SW Beatty JJ Belov K Besson DZ Binns WR Chen C Chen P Clem JM Connolly A Dowkontt PF DuVernois MA Field RC Goldstein D Vieregg AG Hast C Israel MH Javaid A Kowalski J Learned JG Liewer KM Link JT Lusczek E Matsuno S Mercurio BC Miki C Miočinović P Naudet CJ Ng J Nichol RJ Palladino K Reil K Romero-Wolf A Rosen M Ruckman L Saltzberg D Seckel D Varner GS Walz D Wu F 《Physical review letters》2010,105(15):151101
We report the observation of 16 cosmic ray events with a mean energy of 1.5 × 101? eV via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present measurements in the 300-900 MHz range, which are the first self-triggered, first ultrawide band, first far-field, and the highest energy sample of cosmic ray events collected with the radio technique. Their properties are inconsistent with current ground-based geosynchrotron models. The emission is 100% polarized in the plane perpendicular to the projected geomagnetic field. Fourteen events are seen to have a phase inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon. Based on a likelihood analysis, we estimate angular pointing precision of order 2° for the event arrival directions. 相似文献
15.
Research was carried out to estimate the possibility of determining the direction and strength of the ancient geomagnetic
field (H
an
) by natural remanent magnetization (I
n
) of nine oriented samples from traps of the Minor Botuoba Region (Yakutia) aged 260 Ma. Five samples (Pi-10, K-4, K-6, 315–13,
and Ki-2) are characterized by negative polarity of In, while four samples (nos. 334-5, 331–2, 315–11, 299–2) have positive polarity as does the recent geomagnetic field in this
region. The ferrimagnetic constituent of the samples with reverse I
n
polarity appears to be quite variable: samples K-4 and K-5 are characterized by low Curie points (T
c
≈ 200°C) of the ferrimagnetic phase, sample Ki-2 contains single-phase oxidized titanomagnetite with T
c
≈ 310°C, and the T
c
of the Pi-10 ferrimagnetic phase is 540°C. Hence, it may be concluded that the primary remanent magnetization of the first
two samples was formed in a reverse polarity field. These samples also may be used to determine the paleostrength of the geomagnetic
field. The properties of traps containing single-phase oxidized (sample Ki-2) and disintegrated (sample Pi-10) titanomagnetite
require additional investigation. Samples with positive In polarities are characterized by the self-reversal phenomenon upon thermal demagnetization of the natural remanent magnetization,
which was most likely caused by the occurrence of titanomagnetite exsolution textures in ferrimagnetic grains. The paleoinformation
value of the I
n
of these samples is doubtful. 相似文献
16.
V. A. Dergachev S. S. Vasiliev O. M. Raspopov H. Jungner 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(6):847-850
The possible influence of changes in cosmic ray fluxes on climate variability has been the subject of wide speculation in
recent years. New studies show that the interrelation between the parameters of the geomagnetic field and climate can also
be followed on time scales of different lengths. We present our analysis of data on cosmic rays and changes in climate and
the geomagnetic field obtained from different natural archives. 相似文献
17.
From a careful examination of the diurnal variation of cosmic ray intensity at high energies and the interplanetary field
characteristics, the average characteristics of diurnal variation were recently explained by us in terms of a balance between
outward convection and field aligned diffusion, the latter arising out of a positive radial density gradient. In this paper,
we extend this new concept to explain the large variability observed in the diurnal variation on a day-to-day basis and further
demonstrate that the measurement of diurnal anisotropy characteristic of cosmic ray particles on a day-to-day basis can be
used directly to infer the nature and scale sizes of interplanetary field parameters. Comparing with the magnetic field vector,
we show that this simple concept holds good on more than 80% of days. On the rest 20% of days which have a predominant morning
maxima, the diurnal anisotropy characteristics seem to indicate the presence of a significant component of transverse diffusion
current in addition to the normal convection and diffusion flow. Such days are found to be present in the form of trains of
consecutive days and are found to be associated with abrupt changes in the interplanetary field direction having scale sizes
>4 hr. The value ofK
⊥/K
‖ which is normally about ⩽0.05 is found to be ≈1.0 on non-field aligned days. 相似文献
18.
J. W. Bieber 《Il Nuovo Cimento C》1996,19(5):777-790
Summary This is a rapporteur paper for the XXIV International Cosmic-Ray Conference covering topics of anomalous cosmic rays, shock
acceleration, modulation and transport theory, cosmic-ray gradients, corotating interaction regions, coronal-mass ejections,
and solar neutrinos. Among the highlights of the meeting are —conclusive proof that most anomalous cosmic rays are singly
charged,—undisputed detection of anomalous cosmic-ray hydrogen,—discovery of unexpectedly large anisotropies of pickup ions,—observation
of pronounced solar rotational modulation of cosmic-ray fluxes to the highest heliolatitudes (∼80°) probed by the Ulysses
spacecraft, and—new measurements of modulation effects sensitive to particle charge sign.
Rapporteur talk given at the XXIV International Cosmic-Ray Conference, Rome, August 28–September 8, 1995. 相似文献
19.
G. F. Krymsky P. Yu. Gololobov P. A. Krivoshapkin S. K. Gerasimova V. G. Grigoryev S. A. Starodubtsev 《JETP Letters》2014,98(12):769-772
To study long-term variations of the cosmic ray intensity in a wide energy range, a basic model of the modulation of cosmic rays in the heliosphere has been developed at the Institute of Cosmophysical Research and Aeronomy, Siberian Branch, Russian Academy of Sciences. The model involves only one free modulation parameter, the ratio of the regular magnetic field to the turbulent field. It can be used to describe variations of the cosmic ray intensity in a wide energy range of 0.1 to 100 GeV. Attempts have been made to most correctly describe the features of the behavior of the cosmic ray intensity in several solar activity cycles. 相似文献
20.
V. Ye. Sdobnov 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(6):805-807
Based on the data from ground observations of cosmic rays (CRs) obtained by the spectrographic global survey method on the
worldwide network of stations, the variations in the rigidity spectrum and anisotropy of galactic cosmic rays were investigated,
along with changes in the geomagnetic cutoff rigidity in May 2005. A high degree of anisotropy (∼40–60% for the first spherical
harmonics and ∼5–6% for the second spherical harmonics) was observed for particles with a rigidity of 4 GV at the moments
of the maximum modulation of cosmic rays. 相似文献