Relativistic solar cosmic rays

Duggal, S. P.

doi:10.1029/rg017i005p01021

Cited by 107 publications

(73 citation statements)

References 143 publications

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“…It is concluded that the observed higher frequency wiggles in atmospheric "C/12C ratios occurring with time scales of about two hundred years and of 1 to 2 percent in magnitude (de Vries, 1958; Suess, 1970a,b;1979;Damon, Lerman, and Long, 1978), are largely due to solar activity dependent modulation of the galactic cosmic ray flux by solar plasma. These variations override a slowly varying sinusoidal change of about 10 percent in magnitude during the last approximately 8000 years, which is believed to be primarily due to changes in the geomagnetic field.…”

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confidence: 99%

Solar Modulation Effects in Terrestrial Production of Carbon-14

Castagnoli¹,

1980

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ABSTRACT. This paper is concerned with the expected deviations in the production rate of natural 14C on the earth due to changes in solar activity. We review the published estimates of the global production rates of 14C due to galactic and solar cosmic ray particles, and present new estimates of the expected secular variations in 14C production, taking into account the latest information available on galactic cosmic ray modulation and long-term variations in solar activity.Estimated secular variations are related to data on atmospheric 14Cf 12C ratios based on tree rings. It is concluded that the observed higher frequency wiggles in atmospheric "C/12C ratios occurring with time scales of about two hundred years and of 1 to 2 percent in magnitude (de Vries, 1958; Suess, 1970a,b;1979;Damon, Lerman, and Long, 1978), are largely due to solar activity dependent modulation of the galactic cosmic ray flux by solar plasma. These variations override a slowly varying sinusoidal change of about 10 percent in magnitude during the last approximately 8000 years, which is believed to be primarily due to changes in the geomagnetic field. The high frequency modulation effect in 14C production is substantial, about 20 percent, which, considering the response function of the atmosphere (cf Houtermans, Suess, and Oeschger, 1973), is adequate to explain the observed 14C wiggles (also named Suess wiggles or de Vries oscillations) if in the past, periods of large modulation effects and also periods of weak modulation persisted, ie, the sun remained both active and inactive over long periods of time, of the order of several decades to centuries. The pioneering investigations of Eddy (1976; 1977) of the ancient records of solar activity make it plausible that the 14C wiggles in the ancient 14C/12C ratios are primarily due to modulation of galactic cosmic ray flux by a varying sun. Thus, the 14C wiggles are good indicators of solar activity in the past.We also present revised estimates of the production rates of 14C on the earth due to solar flare accelerated cosmic rays and limits of direct accretion of 14C on the earth.

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confidence: 99%

Solar Modulation Effects in Terrestrial Production of Carbon-14

Castagnoli¹,

1980

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“…Up until July 2017, some 71 GLEs had been measured as illustrated in Figure 1, the maximum increases as points together with a smoothed plot of the sunspot number, which is a commonly accepted measure of solar activity. The ionisation chamber data have been normalised to high latitude neutron monitor data [14], while the latter are obtained from [15]. Sea-level monitors have been used but the partial geographic coverage afforded by the available monitors at any given time means that there could have been larger increases at other locations.…”

Section: Ground Level Enhancementsmentioning

confidence: 99%

Extreme Atmospheric Radiation Environments and Single Event Effects

Dyer

Hands

Ryden

et al. 2018

IEEE Trans. Nucl. Sci.

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Abstract-Data from ground-level radiation monitors and cosmogenic nuclides are combined to a give a probability distribution for severe radiation events related to the well quantified event of 23 February 1956. Particle fluxes, single event effects rates and dose rates are calculated for groundlevel and aerospace systems. The event of February 1956 would provide a challenge to air safety while more extreme events seen in historical records would challenge safety-critical ground systems. A new space weather hazard scale based on this event could be used to give rapid assessment of the radiation hazard using high latitude neutron monitor data.

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“…GLEs have been recorded and analysed since 1942, and are numbered sequentially (12). With the exception of GLE5 (February 1956), of the 64 GLEs observed up to 2003, none has presented any risk of attaining an annual dose of 1 mSv (the ICRP recommended public exposure limit) (29).…”

Section: Solar Flaresmentioning

confidence: 99%

Cosmic radiation in commercial aviation

Bagshaw

2008

Travel Medicine and Infectious Disease

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This paper reviews the current knowledge of cosmic radiation and its applicability to commercial aviation. Galactic cosmic radiation emanates from outside the solar system, while occasionally a disturbance in the sun's atmosphere leads to a surge in radiation particles. Protection is provided by the sun's magnetic field, the earth's magnetic field, and the earth's atmosphere. Dose rates are dependent on the altitude, the geomagnetic latitude and the solar cycle. For occupational exposure to ionising radiation, which includes aircrew, the International Commission on Radiological Protection recommends maximum mean body effective dose limits of 20 mSv per year (averaged over 5 years, with a maximum in any one year of 50 mSv). Radiation doses can be measured during flight or may be calculated using a computermodelling program such as CARI, EPCARD, SIEVERT or PCAIRE. Mean ambient equivalent dose rates are in the region of 4 -5 µSv per hour for long-haul pilots and 1 -3 µSv per hour for short-haul, giving an annual mean effective exposure of the order 2 -3 mSv for long-haul and 1 -2 mSv for short-haul pilots. Epidemiological studies of flight crew have not shown any increase in cancer mortality or cancer incidence that could be directly attributable to ionising radiation exposure. Whilst it is accepted that there is no level of radiation exposure below which effects do not occur, all the current evidence indicates that the probability of airline crew or passengers suffering any abnormality or disease as a result of exposure to cosmic radiation is very low.Keywords: Galactic cosmic radiation, solar flare, coronal mass ejection, ground level enhancement (GLE), International Commission on Radiological Protection (ICRP), dose rate effectiveness (DREF), linear energy transfer (LET), relative biological effectiveness (RBE), quality factor (QF), chromosome aberrations, CARI, EPCARD, SIEVERT, PCAIRE. IntroductionThe planet earth is continuously bathed in high-energy ionising radiation known as galactic cosmic radiation (GCR), emanating from outside the solar system, and sporadically exposed to bursts of energetic particles from the sun referred to as solar particle events (SPEs).The main source of GCR is believed to be supernovae (exploding stars), while occasionally a disturbance in the sun's atmosphere (solar flare or coronal mass ejection) leads to a surge of radiation particles with sufficient energy to penetrate the earth's magnetic field and enter the atmosphere. Ionising RadiationIonising radiation refers to subatomic particles that, on interacting with an atom, can directly or indirectly cause the atom to lose an electron or even break apart its nucleus. It is when these events occur in body tissue that health effects may result if the human body's self-repair mechanism fails.Ionising radiation is a normal part of the environment. It is emitted in all normal human tissue cells, and emanates from the ground and some building materials. It is used as a medical diagnostic and treatment tool, and is received from GCR. 2Io...

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Relativistic solar cosmic rays

Cited by 107 publications

References 143 publications

Solar Modulation Effects in Terrestrial Production of Carbon-14

Solar Modulation Effects in Terrestrial Production of Carbon-14

Extreme Atmospheric Radiation Environments and Single Event Effects

Cosmic radiation in commercial aviation

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