About the role of the Sun magnetic field characteristics in the long-term galactic cosmic rays modulation

Recently, there has been a significant trend in magnetic fields on the Sun. The total magnetic field of the Sun from the end of the 22nd cycle of solar activity (SA) has more than halved and this decrease continues. Chan- ges in the magnetic field are the key to all the active phenomena occurring on the Sun and in the heliosphere and, accordingly, to processes in cosmic rays. In long-term CR variations in 23-24 cycles of SA the attenuation of the solar magnetic field is displayed and these variations turned out to be the smallest for the entire time of CR observations. Model calculations of CR modulation for 21-22 and 23-24 cycles of SA showed: with a slight difference in the regression characteristics obtained, the distribution of contributions to the generated CR modulation from the effects of various SA indices is strongly varies in the analyzed periods. Possible reasons for the features of the last two CA cycles are discussed.

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The role of interplanetary magnetic field and solar wind in modulating both galactic cosmic rays and geomagnetic activity

Geophysical Research Letters ◽

10.1029/2000gl003760 ◽

2000 ◽

Vol 27 (13) ◽

pp. 1823-1826 ◽

Cited By ~ 37

Author(s):

I. Sabbah

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Cosmic Rays ◽

Interplanetary Magnetic Field ◽

Geomagnetic Activity ◽

Galactic Cosmic Rays

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Detection of a change in the North-South ratio of count rates of particles of high-energy cosmic rays during a change in the polarity of the magnetic field of the Sun

JETP Letters ◽

10.1134/s0021364015040086 ◽

2015 ◽

Vol 101 (4) ◽

pp. 228-231

Author(s):

A. V. Karelin ◽

O. Adriani ◽

G. C. Barbarino ◽

G. A. Bazilevskaya ◽

R. Bellotti ◽

...

Keyword(s):

Magnetic Field ◽

Cosmic Rays ◽

High Energy ◽

The Sun ◽

High Energy Cosmic Rays ◽

The North ◽

The Magnetic Field

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Long-term evolution of the heliospheric magnetic field inferred from cosmogenic 44Ti activity in meteorites

Astronomy and Astrophysics ◽

10.1051/0004-6361/201730392 ◽

2018 ◽

Vol 610 ◽

pp. A28 ◽

Cited By ~ 2

Author(s):

S. Mancuso ◽

C. Taricco ◽

P. Colombetti ◽

S. Rubinetti ◽

N. Sinha ◽

...

Keyword(s):

Magnetic Field ◽

Ice Cores ◽

Long Term Evolution ◽

Galactic Cosmic Rays ◽

Sunspot Activity ◽

Cosmogenic Isotopes ◽

Heliospheric Magnetic Field ◽

The Past ◽

Term Evolution

Typical reconstructions of historic heliospheric magnetic field (HMF) BHMF are based on the analysis of the sunspot activity, geomagnetic data or on measurement of cosmogenic isotopes stored in terrestrial reservoirs like trees (14C) and ice cores (10Be). The various reconstructions of BHMF are however discordant both in strength and trend. Cosmogenic isotopes, which are produced by galactic cosmic rays impacting on meteoroids and whose production rate is modulated by the varying HMF convected outward by the solar wind, may offer an alternative tool for the investigation of the HMF in the past centuries. In this work, we aim to evaluate the long-term evolution of BHMF over a period covering the past twenty-two solar cycles by using measurements of the cosmogenic 44Ti activity (τ1∕2 = 59.2 ± 0.6 yr) measured in 20 meteorites which fell between 1766 and 2001. Within the given uncertainties, our result is compatible with a HMF increase from 4.87-0.30+0.24 nT in 1766 to 6.83-0.11+0.13 nT in 2001, thus implying an overall average increment of 1.96-0.35+0.43 nT over 235 years since 1766 reflecting the modern Grand maximum. The BHMF trend thus obtained is then compared with the most recent reconstructions of the near-Earth HMF strength based on geomagnetic, sunspot number, and cosmogenic isotope data.

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Long-Term Coherent Periodicities in the Mean Magnetic Field of the Sun

Solar and Stellar Magnetic Fields: Origins and Coronal Effects ◽

10.1007/978-94-009-7181-3_2 ◽

1983 ◽

pp. 23-27 ◽

Cited By ~ 4

Author(s):

V. A. Kotov ◽

L. S. Levitsky

Keyword(s):

Magnetic Field ◽

The Sun ◽

The Mean

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SNR G39.2−0.3, an hadronic cosmic rays accelerator

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2045 ◽

2020 ◽

Vol 497 (3) ◽

pp. 3581-3590

Author(s):

Emma de Oña Wilhelmi ◽

Iurii Sushch ◽

Robert Brose ◽

Enrique Mestre ◽

Yang Su ◽

...

Keyword(s):

Magnetic Field ◽

Cosmic Rays ◽

Supernova Remnants ◽

Gamma Ray ◽

Spectral Energy Distribution ◽

Galactic Cosmic Rays ◽

Spectral Energy ◽

Core Collapse ◽

Heavy Nuclei ◽

The Rich

ABSTRACT Recent results obtained with gamma-ray satellites have established supernova remnants as accelerators of GeV hadronic cosmic rays. In such processes, CRs accelerated in SNR shocks interact with particles from gas clouds in their surrounding. In particular, the rich medium in which core-collapse SNRs explode provides a large target density to boost hadronic gamma-rays. SNR G39.2–0.3 is one of the brightest SNR in infrared wavelengths, and its broad multiwavelength coverage allows a detailed modelling of its radiation from radio to high energies. We reanalysed the Fermi-LAT data on this region and compare it with new radio observations from the MWISP survey. The modelling of the spectral energy distribution from radio to GeV energies favours a hadronic origin of the gamma-ray emission and constrains the SNR magnetic field to be at least ∼100 µG. Despite the large magnetic field, the present acceleration of protons seems to be limited to ∼10 GeV, which points to a drastic slow down of the shock velocity due to the dense wall traced by the CO observations, surrounding the remnant. Further investigation of the gamma-ray spectral shape points to a dynamically old remnant subjected to severe escape of CRs and a decrease of acceleration efficiency. The low-energy peak of the gamma-ray spectrum also suggests that that the composition of accelerated particles might be enriched by heavy nuclei which is certainly expected for a core-collapse SNR. Alternatively, the contribution of the compressed pre-existing Galactic cosmic rays is discussed, which is, however, found to not likely be the dominant process for gamma-ray production.

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The Ulysses fast latitude scans: COSPIN/KET results

Annales Geophysicae ◽

10.5194/angeo-21-1275-2003 ◽

2003 ◽

Vol 21 (6) ◽

pp. 1275-1288 ◽

Cited By ~ 8

Author(s):

B. Heber ◽

G. Sarri ◽

G. Wibberenz ◽

C. Paizis ◽

P. Ferrando ◽

...

Keyword(s):

Magnetic Field ◽

Cosmic Rays ◽

Solar Magnetic Field ◽

Solar Maximum ◽

Cosmic Ray ◽

Galactic Cosmic Rays ◽

Solar Particle Events ◽

Interplanetary Magnetic Fields ◽

Solar Particle ◽

Interplanetary Physics

Abstract. Ulysses, launched in October 1990, began its second out-of-ecliptic orbit in December 1997, and its second fast latitude scan in September 2000. In contrast to the first fast latitude scan in 1994/1995, during the second fast latitude scan solar activity was close to maximum. The solar magnetic field reversed its polarity around July 2000. While the first latitude scan mainly gave a snapshot of the spatial distribution of galactic cosmic rays, the second one is dominated by temporal variations. Solar particle increases are observed at all heliographic latitudes, including events that produce >250 MeV protons and 50 MeV electrons. Using observations from the University of Chicago’s instrument on board IMP8 at Earth, we find that most solar particle events are observed at both high and low latitudes, indicating either acceleration of these particles over a broad latitude range or an efficient latitudinal transport. The latter is supported by "quiet time" variations in the MeV electron background, if interpreted as Jovian electrons. No latitudinal gradient was found for >106 MeV galactic cosmic ray protons, during the solar maximum fast latitude scan. The electron to proton ratio remains constant and has practically the same value as in the previous solar maximum. Both results indicate that drift is of minor importance. It was expected that, with the reversal of the solar magnetic field and in the declining phase of the solar cycle, this ratio should increase. This was, however, not observed, probably because the transition to the new magnetic cycle was not completely terminated within the heliosphere, as indicated by the Ulysses magnetic field and solar wind measurements. We argue that the new A<0-solar magnetic modulation epoch will establish itself once both polar coronal holes have developed.Key words. Interplanetary physics (cosmic rays; energetic particles; interplanetary magnetic fields)

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The Origin of the Most Energetic Galactic Cosmic Rays: Supernova Explosions into Massive Star Plasma Winds

Galaxies ◽

10.3390/galaxies7020048 ◽

2019 ◽

Vol 7 (2) ◽

pp. 48 ◽

Cited By ~ 1

Author(s):

Peter L. Biermann ◽

Philipp P. Kronberg ◽

Michael L. Allen ◽

Athina Meli ◽

Eun-Suk Seo

Keyword(s):

Magnetic Field ◽

Cosmic Rays ◽

Field Strength ◽

Magnetic Field Strength ◽

Space Station ◽

Cosmic Ray ◽

High Energy ◽

Galactic Cosmic Rays ◽

Starburst Galaxy ◽

Supergiant Star

We propose that the high energy Cosmic Ray particles up to the upturn commonly called the ankle, from around the spectral turn-down commonly called the knee, mostly come from Blue Supergiant star explosions. At the upturn, i.e., the ankle, Cosmic Rays probably switch to another source class, most likely extragalactic sources. To show this we recently compiled a set of Radio Supernova data where we compute the magnetic field, shock speed and shock radius. This list included both Blue and Red Supergiant star explosions; both data show the same magnetic field strength for these two classes of stars despite very different wind densities and velocities. Using particle acceleration theory at shocks, those numbers can be transformed into characteristic ankle and knee energies. Without adjusting any free parameters both of these observed energies are directly indicated by the supernova data. In the next step in the argument, we use the Supernova Remnant data of the starburst galaxy M82. We apply this analysis to Blue Supergiant star explosions: The shock will race to their outer edge with a magnetic field that is observed to follow over several orders of magnitude B ( r ) × r ∼ c o n s t . , with in fact the same magnetic field strength for such stellar explosions in our Galaxy, and other galaxies including M82. The speed is observed to be ∼0.1 c out to about 10 16 cm radius in the plasma wind. The Supernova shock can run through the entire magnetic plasma wind region at full speed all the way out to the wind-shell, which is of order parsec scale in M82. We compare and identify the Cosmic Ray spectrum in other galaxies, in the starburst galaxy M82 and in our Galaxy with each other; we suggest how Blue Supergiant star explosions can provide the Cosmic Ray particles across the knee and up to the ankle energy range. The data from the ISS-CREAM (Cosmic Ray Energetics and Mass Experiment at the International Space Station) mission will test this cosmic ray concept which is reasonably well grounded in two independent radio supernova data sets. The next step in developing our understanding will be to obtain future more accurate Cosmic Ray data near to the knee, and to use unstable isotopes of Cosmic Ray nuclei at high energy to probe the “piston” driving the explosion. We plan to incorporate these data with the physics of the budding black hole which is probably forming in each of these stars.

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