scholarly journals INVESTIGATING THE INFLUENCE OF GEOMETRY OF THE HELIOSPHERIC NEUTRAL CURRENT SHEET AND SOLAR ACTIVITY ON MODULATION OF GALACTIC COSMIC RAYS WITH A METHOD OF MAIN COMPONENTS

2020 ◽  
Vol 6 (1) ◽  
pp. 24-28
Author(s):  
Peter Gololobov ◽  
Prokopy Krivoshapkin ◽  
Germogen Krymsky ◽  
Sardaana Gerasimova
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Current Sheet ◽  
Temporal Dynamics ◽  
Neutral Current ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Cosmic Ray Intensity ◽  
Theoretical Concepts ◽  
Main Components

The work studies the cumulative modulating effect of the geometry of the interplanetary magnetic field's neutral current sheet and solar activity on propagation of galactic cosmic rays in the heliosphere. The role of each factor on the modulation of cosmic rays is estimated using a method of main components. The application of the method to experimental data on solar activity, to the tilt angle of the neutral sheet, and cosmic ray intensity for a long period from 1980 to 2018 allows us to reveal the temporal dynamics of roles of these factors in the modulation. The modulation character is shown to strongly depend on the polarity of the Sun’s general magnetic field. Results of the study confirm the existing theoretical concepts of the heliospheric modulation of cosmic rays and reflect its peculiarities for almost four full cycles of solar activity.

scholarly journals INVESTIGATING THE INFLUENCE OF GEOMETRY OF THE HELIOSPHERIC NEUTRAL CURRENT SHEET AND SOLAR ACTIVITY ON MODULATION OF GALACTIC COSMIC RAYS WITH A METHOD OF MAIN COMPONENTS

2020 ◽  
Vol 6 (1) ◽  
pp. 30-35
Author(s):  
Peter Gololobov ◽  
Prokopy Krivoshapkin ◽  
Germogen Krymsky ◽  
Sardaana Gerasimova
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Current Sheet ◽  
Temporal Dynamics ◽  
Neutral Current ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Cosmic Ray Intensity ◽  
Theoretical Concepts ◽  
Main Components

The work studies the cumulative modulating effect of the geometry of the interplanetary magnetic field's neutral current sheet and solar activity on propagation of galactic cosmic rays in the heliosphere. The role of each factor on the modulation of cosmic rays is estimated using a method of main components. The application of the method to experimental data on solar activity, to the tilt angle of the neutral sheet, and cosmic ray intensity for a long period from 1980 to 2018 allows us to reveal the temporal dynamics of roles of these factors in the modulation. The modulation character is shown to strongly depend on the polarity of the Sun’s general magnetic field. Results of the study confirm the existing theoretical concepts of the heliospheric modulation of cosmic rays and reflect its peculiarities for almost four full cycles of solar activity.

Eleven-year modulation of galactic cosmic rays in interplanetary space

1968 ◽  
Vol 46 (10) ◽  
pp. S879-S882 ◽  
Author(s):  
A. N. Chaeakhchyan ◽  
T. N. Charakhchyan
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Large Scale ◽  
Interplanetary Space ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Magnetic Clouds ◽  
The Sun ◽  
Cosmic Ray Intensity ◽  
Stationary Level

Almost the whole increase in the cosmic-ray intensity in the stratosphere during the period of decreasing solar activity (1960–64) was composed of a number of individual events occurring at intervals of 6–12 months. This phenomenon is almost entirely due to the corresponding decrease of solar activity (according to the sunspot number).Several interesting cases were found when solar-activity decreases to a new stationary level took place rapidly (within several days). After such events the cosmic-ray intensity gradually increased to reach a stationary level over a period of about two months. The time, tst, during which the cosmic-ray intensity in interplanetary space (after the above-mentioned events on the sun) approaches a stationary value is about 40, 60, and 80 days according to observations in 1961, 1963, and 1964 respectively.Some results have been obtained on the large-scale magnetic "clouds" which modulate the galactic cosmic rays in interplanetary space: (a) The velocity of propagation of these magnetic clouds is [Formula: see text]. According to the data on u and tst the radius of the sphere around the sun, r, within which the cosmic rays are modulated depends little on solar activity and is equal to 10–15 AU. (b) The density of magnetic clouds in space is either independent of the distance to the sun or decreases less rapidly than the inverse square law suggested by conservation of clouds.[Formula: see text]

scholarly journals Effects of solar activity and galactic cosmic ray cycles on the modulation of the annual average temperature at two sites in southern Brazil

2018 ◽  
Vol 36 (2) ◽  
pp. 555-564 ◽  
Author(s):  
Everton Frigo ◽  
Francesco Antonelli ◽  
Djeniffer S. S. da Silva ◽  
Pedro C. M. Lima ◽  
Igor I. G. Pacca ◽  
...  
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Southern Brazil ◽  
Solar Cycles ◽  
Annual Average ◽  
Average Temperature ◽  
Weather Stations ◽  
Annual Average Temperature

Abstract. Quasi-periodic variations in solar activity and galactic cosmic rays (GCRs) on decadal and bidecadal timescales have been suggested as a climate forcing mechanism for many regions on Earth. One of these regions is southern Brazil, where the lowest values during the last century were observed for the total geomagnetic field intensity at the Earth's surface. These low values are due to the passage of the center of the South Atlantic Magnetic Anomaly (SAMA), which crosses the Brazilian territory from east to west following a latitude of ∼ 26∘. In areas with low geomagnetic intensity, such as the SAMA, the incidence of GCRs is increased. Consequently, possible climatic effects related to the GCRs tend to be maximized in this region. In this work, we investigate the relationship between the ∼ 11-year and ∼ 22-year cycles that are related to solar activity and GCRs and the annual average temperature recorded between 1936 and 2014 at two weather stations, both located near a latitude of 26∘ S but at different longitudes. The first of these stations (Torres – TOR) is located in the coastal region, and the other (Iraí – IRA) is located in the interior, around 450 km from the Atlantic Ocean. Sunspot data and the solar modulation potential for cosmic rays were used as proxies for the solar activity and the GCRs, respectively. Our investigation of the influence of decadal and bidecadal cycles in temperature data was carried out using the wavelet transform coherence (WTC) spectrum. The results indicate that periodicities of 11 years may have continuously modulated the climate at TOR via a nonlinear mechanism, while at IRA, the effects of this 11-year modulation period were intermittent. Four temperature maxima, separated by around 20 years, were detected in the same years at both weather stations. These temperature maxima are almost coincident with the maxima of the odd solar cycles. Furthermore, these maxima occur after transitions from even to odd solar cycles, that is, after some years of intense GCR flux. The obtained results offer indirect mathematical evidence that solar activity and GCR variations contributed to climatic changes in southern Brazil during the last century. A comparison of the results obtained for the two weather stations indicates that the SAMA also contributes indirectly to these temperature variations. The contribution of other mechanisms also related to solar activity cannot be excluded. Keywords. Meteorology and atmospheric dynamics (climatology)

The change in the energy spectrum of galactic cosmic rays over the 11-year solar activity cycle

1968 ◽  
Vol 46 (10) ◽  
pp. S927-S929
Author(s):  
Yu. Stozhkov ◽  
T. N. Charakhchyan
Keyword(s):  
Diffusion Coefficient ◽  
Solar Activity ◽  
Energy Spectrum ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Galactic Cosmic Rays ◽  
Ray Diffusion

The energy spectrum of galactic cosmic rays has been investigated for various periods of the solar activity. In the framework of commonly used ideas about the mechanism of the 11-year variation according to Parker the dependence of the cosmic-ray diffusion coefficient, D, on the particle rigidity, P, was determined. For the form D ≈ vpα the parameter α is found to change during the cycle of the solar activity.[Formula: see text]

scholarly journals The Galactic cosmic ray intensity at the evolving Earth and young exoplanets

2020 ◽  
Author(s):  
Donna Rodgers-Lee ◽  
Aline Vidotto ◽  
Andrew Taylor ◽  
Paul Rimmer ◽  
Turlough Downes
Keyword(s):  
Solar Wind ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
The Sun ◽  
Cosmic Ray Intensity ◽  
Chemical Signature ◽  
Exoplanetary Systems ◽  
Life On Earth ◽  
Galactic Cosmic Ray

<p>Cosmic rays may have contributed to the start of life on Earth. Cosmic rays also influence and contribute to atmospheric electrical circuits, cloud cover and biological mutation rates which are important for the characterisation of exoplanetary systems. The flux of Galactic cosmic rays present at the time when life is thought to have begun on the young Earth or in other young exoplanetary systems is largely determined by the properties of the stellar wind. </p> <p>The spectrum of Galactic cosmic rays that we observe at Earth is modulated, or suppressed, by the magnetised solar wind and thus differs from the local interstellar spectrum observed by Voyager 1 and 2 outside of the solar system. Upon reaching 1au, Galactic cosmic rays subsequently interact with the Earth’s magnetosphere and some of their energy is deposited in the upper atmosphere. The properties of the solar wind, such as the magnetic field strength and velocity profile, evolve with time. Generally, young solar-type stars are very magnetically active and are therefore thought to drive stronger stellar winds. </p> <p>Here I will present our recent results which simulate the propagation of Galactic cosmic rays through the heliosphere to the location of Earth as a function of the Sun's life, from 600 Myr to 6 Gyr, in the Sun’s future. I will specifically focus on the flux of Galactic cosmic rays present at the time when life is thought to have started on Earth (~1 Gyr). I will show that the intensity of Galactic cosmic rays which reached the young Earth, by interacting with the solar wind, would have been greatly reduced in comparison to the present day intensity. I will also discuss the effect that the Sun being a slow/fast rotator would have had on the flux of cosmic rays reaching Earth at early times in the solar system's life.</p> <p>Despite the importance of Galactic cosmic rays, their chemical signature in the atmospheres’ of young Earth-like exoplanets may not be observable with instruments in the near future. On the other hand, it may instead be possible to detect their chemical signature by observing young warm Jupiters. Thus, I will also discuss the HR 2562b exoplanetary system as a candidate for observing the chemical signature of Galactic cosmic rays in a young exoplanetary atmosphere with upcoming missions such as JWST.</p>

Solar modulation of galactic cosmic rays near solar minimum (1965)

1968 ◽  
Vol 46 (10) ◽  
pp. S887-S891 ◽  
Author(s):  
V. K. Balasubrahmanyan ◽  
D. E. Hagge ◽  
F. B. McDonald
Keyword(s):  
Cosmic Rays ◽  
Solar Minimum ◽  
Intensity Variation ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Solar Modulation ◽  
Time Behavior ◽  
Cosmic Ray Intensity ◽  
Radial Gradient

The results of the continuous monitoring of the intensity of cosmic rays (of energy > 50 MeV) with identical G-M counter telescopes flown in satellites IMP I, II, and III and OGO-I are presented along with the differential spectrum studies obtained from balloon flights at Fort Churchill and from satellites. A comparison of the time behavior of the G-M counter data with Deep River neutron monitor data suggests the presence of a "hysteresis" type of behavior due to spectral changes occurring near solar minimum. The existence of this "hysteresis" suggests that the radial gradient of cosmic rays near the earth could be much smaller than the ~ 10%/AU obtained by O'Gallagher and Simpson (1967) and O'Gallagher (1967) at higher energies. The long-term intensity variation of cosmic rays seems to follow the Ap index rather closely in phase, in contrast to sunspot numbers which display a pronounced phase difference with cosmic-ray intensity. The differential spectra of protons and He nuclei have been analyzed in terms of two different models for the propagation in the interplanetary medium. The modulations indicated by the present data seem to disagree with a diffusion coefficient proportional to βR where β and R are the velocity and rigidity of the particle respectively (Jokipii 1966).

Solar rotational period of cosmic rays and solar activity during the maximum phase of solar cycle 24

2021 ◽  
Author(s):  
Prithvi Raj Singh ◽  
A. I. Saad Farid ◽  
Y. P. Singh ◽  
A. K. Singh ◽  
Ayman A. Aly
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
R Package ◽  
Least Square ◽  
Maximum Phase ◽  
Cosmic Ray Intensity ◽  
Solar Cycle 24 ◽  
Cycle 24

Abstract To study the solar rotational oscillation on daily averaged time series of solar activity proxies: sunspot number (SSN), modified coronal index (MCI), solar flare index (FI), and cosmic ray intensity (CRI) are subjected to Lomb/Scargle periodogram, and continuous wavelet transform. For this purpose, we have used data of all the considered parameters from 2012 to 2015, which covers the maximum phase including the polarity reversal period of the solar cycle 24. Both spectral analysis techniques are carried out to study the behavior of 27-days on the time scale of the synodic period and to follow their evolution throughout the epoch. Further, we have used R package RobPer (least square regression) techniques and obtained a significant true period ~27 days is present in this study. It is noted that the ~27-day period of solar activity parameters and cosmic rays is much prominent during the examined period.

Distribution of the number of strong earthquakes and the intensity of space rays during the solar activity cycle

2020 ◽  
Author(s):  
Valery L. Yanchukovsky ◽  
◽  
Anastasiya Yu. Belinskaya ◽  
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Strong Earthquakes ◽  
Cosmic Ray Intensity ◽  
Relationship Of ◽  
The Relationship

The relationship of Earth's seismicity with solar activity is investigated using the results of continuous long–term observations of cosmic ray intensity, solar activity and the number of strong earthquakes. Modulation of the flux of cosmic rays is used as information on the level of solar activity, processes on the Sun and interplanetary medium. The distribution of the number of sunspots, the intensity of cosmic rays and the number of strong earthquakes in the solar cycle is presented.

scholarly journals Unusual decrease of the cosmic ray intensity in May 2019 on the background of the minima solar activity

2021 ◽  
pp. 73-80
Author(s):  
Liudmila Trefilova ◽  
Pavel G. Kobelev ◽  
Anatoly V. Belov ◽  
Eugenia A. Eroshenko ◽  
Anaid A. Melkumyan ◽  
...  
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Active Regions ◽  
Cosmic Ray ◽  
Ground Level ◽  
Neutron Monitors ◽  
Cosmic Ray Intensity ◽  
The Earth ◽  
24Th Cycle ◽  
Field Lines

In May 2019 there was a long and sloping decreasing of cosmic ray’s intensity (up to ~4%), which was observed on neutron monitors. Despite this was a small decreasing compared to quasi-eleven-period variation, it stands out well in 24th cycle of solar activity. According to LASCO/SOHO and STEREO-A data from spectrometer in different UHF bands and from coronograph, there was a series of CMEs which affected on modulation of cosmic rays by creating a series of Forbush decrea - sing, which didn’t restore. This series was connected to two active regions on sun and began on April 30 from “reversed halo” CME. This CME didn’t reach the earth, but led to significant additional modulation of cosmic rays, mostly on east side. Later there was a series of smaller CMEs on May 1-6, which also didn’t reach the earth, but were gradually approaching to Earth. Recent CMEs on 8-9 and 12-13 created a normal Forbush decreasing. In May 2019, cosmic rays shown again, that they can collect information about distant objects of geliosphere and transmit it to Earth. The ground-level detectors sometimes can observe an interaction of interplanetary distur- bances, which didn‘t reach the earth. East CMEs are especially effective, because they closing magnetic field lines beyond the orbit of earth and can interfere the restoring of cosmic ray’s intensity.

THEORETICAL AND EXPERIMENTAL STUDIES OF THE 11-YEAR AND 27-DAY VARIATIONS OF THE GALACTIC COSMIC RAYS INTENSITY AND ANISOTROPY

2005 ◽  
Vol 20 (29) ◽  
pp. 6666-6668 ◽  
Author(s):  
M. V. ALANIA ◽  
A. GIL ◽  
K. ISKRA ◽  
R. MODZELEWSKA ◽  
M. SILUSZYK
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Cosmic Rays ◽  
Energy Range ◽  
Experimental Studies ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Long Period ◽  
Magnetic Cycles ◽  
Galactic Cosmic Ray

The changes of the structure in the energy range of the interplanetary magnetic field (IMF) turbulence versus solar activity can be considered as one of the important reasons of the long period (11-year) modulation of galactic cosmic ray (GCR) intensity; the amplitude of the 27-day variation of GCR anisotropy is greater in the qA > 0 periods than in the qA < 0 periods of the solar magnetic cycles in a good correlation with the similar changes of the 27-day variation of GCR intensity.

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