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1.
This paper summarizes current helicity measurements in the solar active regions (ARs). There is a basic agreement with the
“hemispheric sign rule (HSR)” of the current helicity among different vector magnetographs through two solar cycles, but there
is a large dispersion of the fraction of ARs following the HSR. In our sample, there are 50%–78% ARs in solar cycle 22 and
44%–79% ARs in cycle 23 following the HSR. A variation is also found in the fraction of the ARs following the HSR between
different instruments even when the same ARs are selected. The difference also exists for the same instrument when the selected
ARs are different. There are some differences in the variation of HSR with solar cycle for the individual helicity parameter
inferred from different instruments. Factors which influence the correlation of different data sets are analyzed. 相似文献
2.
The effect of solar features on geospheric conditions leading to geomagnetic storms (GMSs) with planetary index,A
P ≥ 20 and the range of horizontal component of the Earth’s magnetic fieldH such that 250γ <H < 400γ has been investigated using interplanetary magnetic field (IMF), solar wind plasma (SWP) and solar geophysical data
(SGD) during the period 1978–99. Statistically, it is observed that maximum number of GMSs have occurred during the maximum
solar activity years of 21st and 22nd solar cycles. A peculiar result has been observed during the years 1982, 1994 when sunspot
numbers (SSNs) decrease very rapidly while numbers of GMSs increase. No distinct association between yearly occurrence of
disturbed days and SSNs is observed. Maximum number of disturbed days have occurred during spring and rainy seasons showing
a seasonal variation of disturbed days. No significant correlation between magnitude (intensity) of GMSs and importance ofH
α
, X-ray solar flares has been observed. Maximum number of GMSs is associated with solar flares of lower importance, i.e.,
SF during the period 1978-93.H
α
, X-ray solar flares occurred within lower helio-latitudes, i.e., (0–30)°N to (0–30)°S are associated with GMSs. NoH
α
, X-ray solar flares have occurred beyond 40°N or 40°S in association with GMSs. In helio-latitude range (10–40)°N to (10–40)°S,
the 89.5% concentration of active prominences and disappearing filaments (APDFs) are associated with GMSs. Maximum number
of GMSs are associated with solar flares. Coronal mass ejections (CMEs) are related with eruptive prominences, solar flares,
type IV radio burst and they occur at low helio-latitude. It is observed that CMEs related GMS events are not always associated
with high speed solar wind streams (HSSWSs). In many individual events, the travel time between the explosion on the Sun and
maximum activity lies between 58 and 118 h causing GMSs at the Earth. 相似文献
3.
Summary We have analysed ring width sequences of 1.3 My old fossil trees, grown with no water deficit, in Dunarobba forest (Italy).
We find evidence for a modulation period of the annual ring growth widths on time scale of 11 y to 15 y. Since similar modulation
cycles have also been found by other authors in polar ice10Be concentration of the last millennium and in a series of annual ring widths of a same kind of trees grown in Central Europe
of 15–20 My ago, we suggest that such cycles might be related to solar-activity cycles. This would support the hypothesis
of a quasi-periodic behaviour of the solar dynamical system controlled by an oscillator whose fundamental period is of 22–25y,
that can be identified with the Hale cycle; this system would be operational at least since the Miocene era. 相似文献
4.
Summary The analysis of Δ14C in dated tree ring series from 1600 to 1940 AD is presented. The data series is divided into two parts, namely before and
after 1780 AD to better study the characteristic of its cyclicities before, during and after the Maunder Minimum period. The
data after 1780 AD show the presence of significant cyclical variations in the 10–12 year range, similar to the ones observed
in other solar-activity index series. On longer time scales, only the ?Gleissberg? cycle, which appears to modulate the 11
y cycle, seems to be significant. The origin of this last fluctuation in radiocarbon production is influenced by cosmic-ray
intensity variations connected to long-term solar-wind flux variations. The analysis of Δ14C in two independent series of dated tree rings during 1564–1780 AD shows that there is an enhancement in radiocarbon level
during the Maunder Minimum. Our data show that there are time variations of14C production rate even during the Maunder Minimum, as cosmic rays were modulated by the Sun in spite of the very low solar
activity. 相似文献
5.
V. G. Grigoriev S. A. Starodubtsev 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(6):801-804
Variations in the energy spectrum of galactic cosmic rays during Forbush decreases registered in the 20–23 solar activity
cycles are studied, using the data from neutron monitors and the Yakutsk cosmic ray spectrograph. It is shown that the Forbush
decreases in the 23rd cycle of solar activity had a harder energy spectrum than in the three previous cycles, due to the relatively
low level of turbulence of the interplanetary magnetic field during the 23rd solar activity cycle. 相似文献
6.
It is well known today that a continuous stream of highly ionized plasma is emitted from the Sun’s surface. This plasma is called the solar wind and consists of protons, electrons, and light nuclei. The solar wind pushes the solar magnetic field into interplanetary space to form the interplanetary magnetic field. The interplanetary magnetic field is a dynamical system that depends on the solar cycle and the Sun’s rotation phase. Thus, the Solar System is a natural plasma physics laboratory with an enormous multitude of different effects showing the current state of the system. By recording cosmic-ray fluxes, one can study the behavior of the interplanetary magnetic field and obtain information about processes that occur both on the Sun’s surface and throughout the Solar System. The main short-time variations in cosmic-ray intensity include the 27-day variations and the Forbush decreases. These variations are caused by complex solar plasma structures, which are generated by different processes on the Sun’s surface and propagate through space in a wide range of velocities. Cosmic-ray fluxes recorded with the PAMELA magnetic spectrometer on board the Resurs DK1 satellite in 2006–2016 are used to show some examples of cosmic-ray variations. 相似文献
7.
In the Kompaneets approximation, we study the propagation of a shock front from the explosion point in an inhomogeneous medium
with a power-law variation of the density characterized by the exponent n=2, which is important and corresponds to the external
parts of the solar and stellar coronas. An unexpectedly simple exact solution, which allows us to clarify the structure of
the general solution under an arbitrary monotonous law of the density variation, was obtained. The results for the plane case
are compared with Korikanskii’s results for a noncentral point explosion in a radially stratified medium. A correspondence
between the exact solutions is established in these cases, and a new solution for the noncentral explosion is obtained for
the case of a density with a singularity at a finite radius, which decreases quadratically at infinity.
Radioastronimical Institute of the National Academy of Sciences, Khar’kov, Ukraine; Research Institute of Physics, State University,
Rostov-on-Don, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 6, pp. 683–698, June,
1998. 相似文献
8.
D. G. Baranov Yu. F. Gagarin V. A. Dergachev E. A. Yakubovskii 《Technical Physics》1999,44(9):1084-1088
Results are presented from investigations of Fe-group nuclei in galactic and solar cosmic rays in the energy ranges 30–210
MeV/n and 7–210 MeV/n in various phases of the solar cycles. Spectra of Fe particles have been obtained with high energy resolution
as a result of exposing PLATAN chambers, made up of layers of a polyethyelene terephthalate solid-state track detector, for
between one and three years on the Salyut-6, Salyut-7, and Mir space stations, orbiting at an inclination of 51.6° to the
plane of the equator and at an altitude of 350–400 km. Measurements were made of the energy spectra of Fe particles from a
unique event, the series of solar flares of September 29 and October 19–29, 1989, which is the most powerful of those recorded
and measured over the entire history of cosmic ray research. A modern model of particle penetration inside the Earth’s magnetosphere,
developed at the Institute of Nuclear Physics at Moscow State University, is used to compare the measured spectrum with measurements
made using the solid-state track detector in the HIIS experiment on the LDEF station, and with extramagnetospheric measurements
made using electronic equipment on the IMP-8 satellite and the Galileo space station. It is shown that the solid-state track
detector technique has advantages for obtaining the characteristics of the energy spectrum.
Zh. Tekh. Fiz. 69, 94–98 (September 1999) 相似文献
9.
Summary The cyclogram method of time series analysis has been used to analyse10Be data (1181–1800 AD) and δ18O data (1181–1960 AD) from an artic ice core and thermoluminescence data (1181–1960 AD) from a Mediterranean sediment core.
The10Be concentrations were determined at the ETH Zurich. The δ18O values were measured at the University of Copenhagen. The TL measurements were performed at the Istituto di Cosmo-geofisica
del C.N.R., Torino. Common mean periodicities of 10.75 y are found for the period 1505 to 1710 AD in TL and10Be and of 11.4 y for the period 1715 to 1880 in TL and δ18O. This periodicity was found in the solar sunspot (R
z) series analysed in the same way, from 1825 to 1905. This supports the argument that the common periodicities found in the
long-running series are peculiar of the solar activity in the past.
Presented at theThird International Symposium on Accelerator Mass Spectrometry (Zurch, April 10–13, 1984). 相似文献
10.
G. E. Kocharov 《Technical Physics》1999,44(9):1081-1083
Results of highly accurate measurements of the radiocarbon concentration in the annual growth rings of trees over the last
400 years are presented. The temporal behavior of the intensity of galactic cosmic rays is reconstructed for the first time
for the periods before, during, and after a deep and extended solar activity minimum — the Maunder minimum (1645–1715). It
was established that even during the epoch of a deep solar minimum, the intensity of the galactic cosmic rays experienced
solar modulation. The time profile of the generation of high-energy gamma radiation from the supernova explosion of 1006 is
established. It is shown that processes of particle acceleration and generation of high-energy gamma rays take place with
a three-year delay relative to the onset of the optical flare. The time profile of the generation of solar cosmic rays was
obtained for the first time over the last thirty cycles of solar activity by precision measurements of the nitrate content
in the polar ice cap. It is shown that solar flares accompanied by the generation of cosmic rays occur during the growth and
decay phase of solar activity (measured by the Wolf numbers). Research prospects in the field of experimental paleoastrophysics
are discussed.
Zh. Tekh. Fiz. 69, 90–93 (September 1999) 相似文献
11.
We present the results of analysis of the spectra of amplitude scintillations at a frequency of 150 MHz and a difference phase
at frequencies of 150 and 400 MHz, which were obtained in the experiment on radio tomography of artificial ionospheric turbulence
(AIT) excited by the mid-latitude high-power “Sura” heating facility [1]. We used the data on radio probing of the AIT region
at a frequency of 150 MHz by signals from artificial satellites in near-polar circular orbits at altitudes of 1000 km above
the Earth’s surface. The signals were received simultaneously at three spaced apart points located at distances of about 100–150
km from each other along the projection of the satellite trajectory onto the Earth’s surface. The analysis of the data shows
that in the range of scales smaller than 0.5–1.0 km across the geomagnetic field, the AIT spatial spectrum can be described
by the power-law function with the spectral index p⊥ = 1.7–2.5. For irregularities with the same transverse scales, the spectral index in the direction of the magnetic field
amounts to p‖ = 5–7.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 8, pp. 722–730, August 2007 相似文献
12.
It is demonstrated that the generally accepted treatment of the second law of thermodynamics is incorrect when the statement
of the maximum limiting efficiency of the forward Carnot cycle is applied to the reverse cycles. An analysis of reversible
cycles compared with the Carnot cycle shows that the reverse Carnot cycle has the lowest efficiency of all reverse cycles.
A new characteristic is proposed — the thermal efficiency of reverse cycles, and a generalized theorem is put forward for
the additivity of the thermal efficiencies of the forward and reverse cycles. A formulation of the second law of thermodynamics
is suggested from the point of view of the efficiency of reverse cycles.
Zh. Tekh. Fiz. 69, 11–14 (June 1999) 相似文献
13.
The vertical column abundance of NO2 is measured using direct sunlight. The solar spectra in the wavelength region of 430–450 nm observed from the earth’s surface
are ratioed with a reference spectrum taken from the Kitt Peak Solar Flux Atlas. The large Fraunhofer features (20–40%) are
eliminated by wavelength correction, resolution matching and ratioing of observed spectra to the reference. The retrieved
values of the NO2 vertical column density are in a range of (2–15)x1016 molecules/cm2 with an accuracy of better than 3%. This result demonstrates the usefulness of the Kitt Peak Atlas in the study of tropospheric
NO2 concentration, giving a standard extraterrestrial solar spectrum for the case in which the Langley method is not readily
applicable. 相似文献
14.
L. P. Avakyants P. Yu. Bokov G. B. Galiev V. é. Kaminskii V. A. Kulbachinskii V. G. Mokerov A. V. Chervyakov 《Optics and Spectroscopy》2002,93(6):857-861
Photoreflectance spectra are measured in heterostructures with coupled quantum wells at room temperature. The energies of
the optical transitions are determined, and their variation with the well width and barrier thickness is studied. The experimental
results are compared with the theoretically calculated electron-hole transition energies. Good agreement is obtained for narrow
wells.
__________
Translated from Optika i Spektroskopiya, Vol. 93, No. 6, 2002, pp. 929–934.
Original Russian Text Copyright ? 2002 by Avakyants, Bokov, Galiev, Kaminskiĭ, Kul’bachinskiĭ, Mokerov, Chervyakov. 相似文献
15.
A.S. Joshipura S.D. Rindani 《The European Physical Journal C - Particles and Fields》2000,14(1):85-89
We discuss an extended model which naturally leads to mass scales and mixing angles relevant for understanding both the solar and atmospheric neutrino
anomalies in terms of the vacuum oscillations of the three known neutrinos. The model uses a softly broken –– symmetry and contains a heavy scale GeV. The –– symmetric neutrino masses solve the atmospheric neutrino anomaly while breaking of –– generates the highly suppressed radiative mass scale needed for the vacuum solution of the solar neutrino problem. All the neutrino masses in the model are inversely related
to , thus providing seesaw-type of masses without invoking any heavy right-handed neutrinos. The possible embedding of the model
into an SU(5) grand unified theory is discussed.
Received: 5 August 1999 / Revised version: 18 November 1999 / Published online: 6 April 2000 相似文献
16.
We analyze free oscillations in a digital second-order system with saturation nonlinearity and truncation in modulus after
summation. The limiting cycles are found to exist in the system. Analytical and experimental estimates for their periods and
existence conditions are given.
Yaroslavl’ State University, Yaroslavl’, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol.
43, No. 2, pp. 174–181, February 2000. 相似文献
17.
The solar activity in the current, that is, the 24th, sunspot cycle is analyzed. Cyclic variations in the sunspot number (SSN) and radiation fluxes in various spectral ranges have been estimated in comparison with the general level of the solar radiation, which is traditionally determined by the radio emission flux F10.7 at a wavelength of 10.7 cm (2.8 GHz). The comparative analysis of the variations in the solar constant and solar indices in the UV range, which are important for modeling the state of the Earth’s atmosphere, in the weak 24th cycle and strong 22nd and 23rd cycles has shown relative differences in the amplitudes of variations from the minimum to the maximum of the cycle. The influence of the hysteresis effect between the activity indices and F10.7 in the 24th cycle, which is taken into account here, makes it possible to refine the forecast of the UV indices and solar constant depending on the quadratic regression coefficients that associate the solar indices with F10.7 depending on the phase of the cycle. 相似文献
18.
This paper presents data on relativistic electron fluxes (1.5–3 MeV) measured at altitudes of 360–500 km onboard the CORONAS-F
satellite. The monthly average fluxes of these particles in the Earth’s outer radiation belt are shown to greatly increase
from August 2001 to September 2003. The monthly average fluxes of relativistic electrons in the Earth’s outer radiation belt
in the period from August 2001 to July 2004 are also found to be strongly correlated with the monthly average velocities of
the solar wind and values of the Kp-index, with this correlation breaking down after July 2004. This paper discusses the possible
reasons for the discovered patterns. 相似文献
19.
V. S. Makhmutov V. G. Kurt B. Yu. Yushkov V. V. Grechnev P. Kaufmann J. -P. Raulin G. A. Bazilevskaya Yu. I. Stozhkov 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(6):747-750
We analyze experimental data on the temporal behavior of fluxes and energy spectra of hard solar X-ray and gamma radiation
in the energy range of 0.015 to 300 MeV, obtained onboard the CORONAS-F satellite during a solar flare on August 25, 2001.
These data are compared with measurements of the radio emission fluxes over the wide frequency range of 1–405 GHz. For our
analysis, we use data obtained onboard the YOHKOH, TRACE and GOES satellites, along with ground-based observations of this
solar event using the Solar Submillimeter Telescope (SST; Argentina). For the first time, we find nearly simultaneous changes
in the energy spectra of gamma radiation over the range 10–150 MeV and the frequency spectrum of radio emission at the beginning
and during a impulsive phase of this event (whose duration did not exceed three minutes). 相似文献
20.
G. A. Bazilevskaya M. B. Krainev V. S. Makhmutov A. K. Svirzhevskaya N. S. Svirzhevsky Yu. L. Stozhkov 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(6):782-785
The minimum between the 23rd and 24th cycles of solar activity was unusually deep and extended. The modulation of cosmic rays
was minimal for the more than 70-year-long period of direct measurements. The data from stratospheric measurements by the
Lebedev Physical Institute suggest that the flux of cosmic rays with more than 100 MeV/nucleon of energy exceeded the highest
ever observed level (May 1965) by almost 12%. However, the ground-based neutron monitors sensitive to relatively high energies
indicated that the flux of cosmic rays increased by less than 3%. This work compares the variations in the cosmic rays over
periods of five minima of solar activity (the 20th to the 24th cycle). It is shown that in late 2008, an extra flux of particles
with energies less than several GeV/nucleon was detected in the Earth’s orbit. A similar (though far smaller in scale) phenomenon
was also observed in 1987 at the same orientation of the Sun’s magnetic field A < 0, but was not observed in epochs where A > 0. 相似文献