Initial conditions for radiation analysis: Models of galactic cosmic rays and solar particle events

2006 ◽  
Vol 38 (6) ◽  
pp. 1182-1190 ◽  
Author(s):  
R. Nymmik
Keyword(s):  
Cosmic Rays ◽  
Initial Conditions ◽  
Galactic Cosmic Rays ◽  
Solar Particle Events ◽  
Solar Particle ◽  
Analysis Models

scholarly journals The Ulysses fast latitude scans: COSPIN/KET results

2003 ◽  
Vol 21 (6) ◽  
pp. 1275-1288 ◽  
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)

Modelling of aircrew radiation exposure from galactic cosmic rays and solar particle events

2007 ◽  
Vol 124 (4) ◽  
pp. 289-318 ◽  
Author(s):  
M. Takada ◽  
B. J. Lewis ◽  
M. Boudreau ◽  
H. Al Anid ◽  
L. G. I. Bennett
Keyword(s):  
Cosmic Rays ◽  
Radiation Exposure ◽  
Galactic Cosmic Rays ◽  
Solar Particle Events ◽  
Solar Particle

Tissue Equivalence Study of a Novel Diamond-Based Microdosimeter for Galactic Cosmic Rays and Solar Particle Events

2014 ◽  
Vol 61 (4) ◽  
pp. 1544-1551 ◽  
Author(s):  
Jeremy A. Davis ◽  
Susanna Guatelli ◽  
Marco Petasecca ◽  
Michael L. F. Lerch ◽  
Mark I. Reinhard ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Galactic Cosmic Rays ◽  
Solar Particle Events ◽  
Solar Particle

scholarly journals MODELING OF AIRCREW RADIATION EXPOSURE FROM GALACTIC COSMIC RAYS AND SOLAR PARTICLE EVENTS

2007 ◽  
pp. 233-243
Author(s):  
M. TAKADA ◽  
B. J. LEWIS ◽  
M. BOUDREAU ◽  
H. AL ANID ◽  
L. G. I. BENNETT
Keyword(s):  
Cosmic Rays ◽  
Radiation Exposure ◽  
Galactic Cosmic Rays ◽  
Solar Particle Events ◽  
Solar Particle

scholarly journals Transport of Solar Energetic Particles

1994 ◽  
Vol 142 ◽  
pp. 567-576
Author(s):  
Wolfgang Dröge
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Cosmic Rays ◽  
Linear Theory ◽  
Interplanetary Medium ◽  
Galactic Cosmic Rays ◽  
Transport Parameters ◽  
Solar Cosmic Rays ◽  
Solar Particle Events ◽  
Solar Particle

AbstractNew developments in the understanding of the interplanetary transport of solar cosmic rays are reviewed. Based on carefully analyzed solar particle events observed on the Helios and ISEE 3 spacecraft, the relation of transport parameters to the structure of the interplanetary magnetic field is discussed. Special emphasis is given to a comparison of particle mean free paths determined from fits to intensity and anisotropy profiles with theoretical predictions derived from magnetic field spectra measured at the time of the solar particle event. Different aspects of the turbulence and wave models for the magnetic fluctuations are considered, including the effects resulting from the finite temperature of the plasma and of resonance broadening. It is found that a modified quasi-linear theory of particle scattering taking into account the effects of plasma waves propagating with respect to the average solar wind flow and the proper treatment of the dispersion relation at high wavenumber gives results which are in several cases in good agreement with particle observations in the interplanetary medium between 0.3 and 1 AU, indicating that quasi-linear theory is probably a good approximation to a full theory of solar particle transport. This has important implications for other astrophysical problems where quasi-linear theory is often used, such as the propagation and acceleration of Galactic cosmic rays and particle acceleration at shock waves.Subject headings: acceleration of particles — cosmic rays — interplanetary medium — MHD — solar wind — Sun: particle emission

scholarly journals Cosmic-Ray Transport and Acceleration

1994 ◽  
Vol 142 ◽  
pp. 926-936
Author(s):  
Reinhard Schlickeiser
Keyword(s):  
Cosmic Rays ◽  
Decisive Role ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Diffusion Term ◽  
Solar Particle Events ◽  
High Energy Cosmic Rays ◽  
Propagation Parameters ◽  
And Diffusion

AbstractWe review the transport and acceleration of cosmic rays concentrating on the origin of galactic cosmic rays. Quasi-linear theory for the acceleration rates and propagation parameters of charged test particles combined with the plasma wave viewpoint of modeling weak cosmic electromagnetic turbulence provides a qualitatively and quantitatively correct description of key observations. Incorporating finite frequency effects, dispersion, and damping of the plasma waves are essential in overcoming classical discrepancies with observations as the Kfit - Kql discrepancy of solar particle events. We show that the diffusion-convection transport equation in its general form contains spatial convection and diffusion terms as well as momentum convection and diffusion terms. In particular, the latter momentum diffusion term plays a decisive role in the acceleration of cosmic rays at super-Alfvénic supernova shock fronts, and in the acceleration of ultra-high-energy cosmic rays by distributed acceleration in our own galaxy.Subject headings: acceleration of particles — convection — cosmic rays — diffusion — shock waves

scholarly journals Variations in Radiocarbon Production in the Earth's Atmosphere

Radiocarbon ◽  
1980 ◽  
Vol 22 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Serge A Korff ◽  
Rosalind B Mendell
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Solar Flare ◽  
Production Rate ◽  
Sunspot Number ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Solar Particle Events

We have investigated solar phenomena associated with unusual changes in the production rates of 14C in the atmosphere. 14C is produced in interactions of cosmic ray neutrons with nitrogen in the atmosphere. Intensity of the neutrons varies globally and fluctuates with time as a result of interactions of galactic cosmic rays which generate neutrons with plasma and magnetic fields of the solar wind. We estimate the total mean production rate of 14C for solar cycle 20, specifically 1965 to 1975, to be 2.25 ± 0.1 nuclei-cm−2sec−1 from galactic cosmic rays alone, with negligible integrated contribution from solar particle events. Annual averages of Rz, the Zurich sunspot number, and the production rate of 14C, n(14C), were related by n(14C) = 2.60–5.53 × 10–3 Rz ± 3 percent. The contribution of solar flare particles and the zero sunspot limit are discussed with relation to major fluctuations that appear in the radiocarbon versus dendrochronology over short (∼100 years) integration times.

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