Variation of Proton Flux with Atmospheric Depth Between 10 and 50 g/cm2 at l = 47° S. Geomagnetic

Proton fluxes at atmospheric depths between 10 and 50 g/cm2 have been measured using nuclear emulsions during a series of balloon flights over Melbourne (A = 47� S. geomagnetic) in the period November 1961-April 1962. The proton flux J(x) decreases with increasing depth within this region. It can be represented by the relation log J(x) = (3�05�0�02)-(2�36�0�66)xlO-3x and, when extrapolated, gives the flux at the top of the atmosphere to be 1120�50 protons m-2 steradian-1 S-l.

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Experimental feature in the primary-proton flux at energies above 10 TeV according to the results of searches for primary particles in nuclear emulsions exposed in the stratosphere (RUNJOB Experiment)

Physics of Atomic Nuclei ◽

10.1134/s1063778808020075 ◽

2008 ◽

Vol 71 (2) ◽

pp. 280-284 ◽

Cited By ~ 6

Author(s):

I. S. Zayarnaya

Keyword(s):

Proton Flux ◽

Primary Proton ◽

Nuclear Emulsions ◽

Experimental Feature ◽

Primary Particles

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Cosmic-ray flux variation with height in the atmosphere

Canadian Journal of Physics ◽

10.1139/p68-407 ◽

1968 ◽

Vol 46 (10) ◽

pp. S1020-S1022 ◽

Cited By ~ 2

Author(s):

B. S. Chow ◽

K. K. Wu ◽

N. Simpson ◽

V. D. Hopper

Keyword(s):

Cosmic Radiation ◽

Cosmic Ray ◽

Geiger Counter ◽

Proton Flux ◽

Atmospheric Depth ◽

Altitude Range ◽

Flux Variation ◽

Star Production ◽

Cosmic Ray Flux ◽

Made In

Analysis of emulsions exposed to cosmic radiation at atmospheric depths between 10 and 40 g/cm2 at λ = 47 °S geomagnetic on 11 December 1964 shows that there is little variation with altitude in proton flux in this altitude range. However, the total star production rate increases with increasing atmospheric depth but with a smaller slope than that measured by Geiger counter. Preliminary results obtained from exposures made in November 1965 at 8.5, 28.4, and 58 g/cm2 show that the values of proton flux at 8.5 and 58 g/cm2 are lower than that at 28.4 g/cm2. A study of the rate of production of stars at λ = 43° S and 9 g/cm2 over the period April 1962 to September 1966 shows some correlation with the ground-based neutron monitor count rate. The proton flux at the top of the atmosphere at latitude 47° S is estimated as 900 ± 100 protons/m2 sr s.

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OMEP-EOR: A MeV proton flux specification model for Electric Orbit Raising missions

Journal of Space Weather and Space Climate ◽

10.1051/swsc/2021038 ◽

2021 ◽

Author(s):

Antoine Brunet ◽

Angélica Sicard ◽

Constantinos Papadimitriou ◽

Didier Lazaro ◽

Pablo Caron

Keyword(s):

Radiation Belt ◽

Temporal Dynamics ◽

Radiation Belts ◽

Proton Flux ◽

Radiation Environment ◽

Solar Arrays ◽

Proton Fluxes ◽

Van Allen Probes ◽

Spectrum Distribution ◽

Gp Model

Electric Orbit Raising (EOR) for telecommunication satellites has allowed significant reduction in on-board fuel mass, at the price of extended transfer durations. These relatively long transfers, which usually span a few months, cross large spans of the radiation belts, resulting in significant exposure of the spacecraft to space radiations. Since they are not very populated, the radiation environment of intermediate regions of the radiation belts is less constrained than on popular orbits such as LEO or GEO on standard environment models. In particular, there is a need for more specific models for the MeV energy range proton fluxes, responsible for solar arrays degradations, and hence critical for EOR missions. As part of the ESA ARTES program, ONERA has developed a specification model of proton fluxes dedicated for EOR missions. This model is able to estimate the average proton fluxes between 60 keV and 20MeV on arbitrary trajectories on the typical durations of EOR transfers. A global statistical model of the radiation belts was extracted from the Van Allen Probes (RBSP) RBSPICE data. For regions with no or low sampling, simulation results from the Salammbô radiation belt model were used. A special care was taken to model the temporal dynamics of the belts on the considered mission durations. A Gaussian Process (GP) model was developed, allowing to compute analytically the distribution of the average fluxes on arbitrary mission durations. Satellites trajectories can be flown in the resulting global distribution, yielding the proton flux spectrum distribution as seen by the spacecraft. We show results of the model on a typical EOR trajectory. The obtained fluxes are compared to the standard AP8 model, the AP9 model, and validated using the THEMIS satellites data.We illustrate the expected e ect on solar cell degradation, where our model is showing an increase of up to 20% degradation prediction compared to AP8.

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The coupling between the solar wind and proton fluxes at GEO

Annales Geophysicae ◽

10.5194/angeo-31-1631-2013 ◽

2013 ◽

Vol 31 (10) ◽

pp. 1631-1636 ◽

Cited By ~ 2

Author(s):

R. J. Boynton ◽

S. A. Billings ◽

O. A. Amariutei ◽

I. Moiseenko

Keyword(s):

Solar Wind ◽

Wind Velocity ◽

Solar Wind Velocity ◽

Proton Flux ◽

Dst Index ◽

Proton Fluxes ◽

Angle Function ◽

The Relationship ◽

Energy Channels ◽

Imf Clock Angle

Abstract. The relationship between the solar wind and the proton flux at geosynchronous Earth orbit (GEO) is investigated using the error reduction ratio (ERR) analysis. The ERR analysis is able to search for the most appropriate inputs that control the evolution of the system. This approach is a black box method and is able to derive a mathematical model of a system from input-output data. This method is used to analyse eight energy ranges of the proton flux at GEO from 80 keV to 14.5 MeV. The inputs to the algorithm were solar wind velocity, density and pressure; the Dst index; the solar energetic proton (SEP) flux; and a function of the interplanetary magnetic field (IMF) tangential magnitude and clock angle. The results show that for lowest five energy channels (80 to 800 keV) the GEO proton fluxes are controlled by the solar wind velocity with a lag of two to three days. However, above 350 keV, the SEP fluxes, accounts for a significant portion of the GEO proton flux variance. For the highest three energy channels (0.74 to 14.5 MeV), the SEPs account for the majority of the ERR. The results also show an anisotropy of protons with gyrocenters inside GEO and outside GEO, where the protons inside GEO are controlled partly by the Dst index and also an IMF-clock angle function.

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Modulation of Extracellular Proton Fluxes from Retinal Horizontal Cells of the Catfish by Depolarization and Glutamate

The Journal of General Physiology ◽

10.1085/jgp.200709737 ◽

2007 ◽

Vol 130 (2) ◽

pp. 169-182 ◽

Cited By ~ 28

Author(s):

Matthew A. Kreitzer ◽

Leon P. Collis ◽

Anthony J.A. Molina ◽

Peter J.S. Smith ◽

Robert Paul Malchow

Keyword(s):

Nmda Receptor ◽

Cell Membrane ◽

Ictalurus Punctatus ◽

Receptor Agonist ◽

Metabotropic Glutamate Receptor ◽

Proton Flux ◽

Horizontal Cells ◽

Kainate Receptor ◽

Extracellular Potassium ◽

Proton Fluxes

Self-referencing H+-selective microelectrodes were used to measure extracellular proton fluxes from cone-driven horizontal cells isolated from the retina of the catfish (Ictalurus punctatus). The neurotransmitter glutamate induced an alkalinization of the area adjacent to the external face of the cell membrane. The effect of glutamate occurred regardless of whether the external solution was buffered with 1 mM HEPES, 3 mM phosphate, or 24 mM bicarbonate. The AMPA/kainate receptor agonist kainate and the NMDA receptor agonist N-methyl-d-aspartate both mimicked the effect of glutamate. The effect of kainate on proton flux was inhibited by the AMPA/kainate receptor blocker CNQX, and the effect of NMDA was abolished by the NMDA receptor antagonist DAP-5. Metabotropic glutamate receptor agonists produced no alteration in proton fluxes from horizontal cells. Depolarization of cells either by increasing extracellular potassium or directly by voltage clamp also produced an alkalinization adjacent to the cell membrane. The effects of depolarization on proton flux were blocked by 10 μM nifedipine, an inhibitor of L-type calcium channels. The plasmalemma Ca2+/H+ ATPase (PMCA) blocker 5(6)-carboxyeosin also significantly reduced proton flux modulation by glutamate. Our results are consistent with the hypothesis that glutamate-induced extracellular alkalinizations arise from activation of the PMCA pump following increased intracellular calcium entry into cells. This process might help to relieve suppression of photoreceptor neurotransmitter release that results from exocytosed protons from photoreceptor synaptic terminals. Our findings argue strongly against the hypothesis that protons released by horizontal cells act as the inhibitory feedback neurotransmitter that creates the surround portion of the receptive fields of retinal neurons.

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Basolateral membrane Na/base cotransport is dependent on CO2/HCO3 in the proximal convoluted tubule.

The Journal of General Physiology ◽

10.1085/jgp.90.6.833 ◽

1987 ◽

Vol 90 (6) ◽

pp. 833-853 ◽

Cited By ~ 39

Author(s):

R Krapf ◽

R J Alpern ◽

F C Rector ◽

C A Berry

Keyword(s):

Buffer Capacity ◽

Basolateral Membrane ◽

Proximal Convoluted Tubule ◽

Proton Flux ◽

Proton Fluxes ◽

Cell Ph ◽

Absolute Requirement ◽

Ambient Co2

The mechanism of basolateral membrane base transport was examined in the in vitro microperfused rabbit proximal convoluted tubule (PCT) in the absence and presence of ambient CO2/HCO3- by means of the microfluorometric measurement of cell pH. The buffer capacity of the cells measured using rapid NH3 washout was 42.8 +/- 5.6 mmol.liter-1.pH unit-1 in the absence and 84.6 +/- 7.3 mmol.liter-1.pH unit-1 in the presence of CO2/HCO3-. In the presence of CO2/HCO3-, lowering peritubular pH from 7.4 to 6.8 acidified the cell by 0.30 pH units and lowering peritubular Na from 147 to 0 mM acidified the cell by 0.25 pH units. Both effects were inhibited by peritubular 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonate (SITS). In the absence of exogenous CO2/HCO3-, lowering peritubular pH from 7.4 to 6.8 acidified the cell by 0.25 pH units and lowering peritubular Na from 147 to 0 mM decreased cell pH by 0.20 pH units. Lowering bath pH from 7.4 to 6.8 induced a proton flux of 643 +/- 51 pmol.mm-1.min-1 in the presence of exogenous CO2/HCO3- and 223 +/- 27 pmol.mm-1.min-1 in its absence. Lowering bath Na from 147 to 0 mM induced proton fluxes of 596 +/- 77 pmol.mm-1.min-1 in its absence. The cell acidification induced by lowering bath pH or bath Na in the absence of CO2/HCO3- was inhibited by peritubular SITS or by acetazolamide, whereas peritubular amiloride had no effect. In the absence of exogenous CO2/HCO3-, cyanide blocked the cell acidification induced by bath Na removal, but was without effect in the presence of exogenous CO2/HCO3-. We reached the following conclusions. (a) The basolateral Na/base n greater than 1 cotransporter in the rabbit PCT has an absolute requirement for CO2/HCO3-. (b) In spite of this CO2 dependence, in the absence of exogenous CO2/HCO3-, metabolically produced CO2/HCO3- is sufficient to keep the transporter running at 30% of its control rate in the presence of ambient CO2/HCO3-. (c) There is no apparent amiloride-sensitive Na/H antiporter on the basolateral membrane of the rabbit PCT.

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