ROCKET MEASUREMENTS IN PROTON AURORA

1967 ◽  
Vol 45 (10) ◽  
pp. 3247-3255 ◽  
Author(s):  
B. A. Whalen ◽  
I. B. McDiarmid ◽  
E. E. Budzinski
Keyword(s):  
Pitch Angle ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Electron Spectra ◽  
Source Mechanisms ◽  
Electron Intensity ◽  
Proton Precipitation ◽  
Rocket Measurements ◽  
Short Time ◽  
Proton Aurora

Proton and electron intensities, energy spectra, and angular distributions derived from a recent rocket flight launched into a 40-rayleigh Hβ aurora are reported. High-intensity proton precipitation (~0.45 erg cm−2 s−1 for protons with energies above 30 keV) was detected throughout the flight above 100 km, whereas the electron intensity was above the limit of detectability for only a short time. The proton and electron spectra and angular distributions in the 20–60 keV energy range were found to be remarkably similar, with angular distributions being isotropic over the pitch-angle range 0–90°, and with e-folding energies of about 12 keV and 18 keV for protons and electrons respectively. The results are interpreted in terms of current magnetospheric models, and are shown to place certain restrictions on the source mechanisms.

ROCKET OBSERVATIONS OF ELECTRON PITCH-ANGLE DISTRIBUTIONS DURING AURORAL SUBSTORMS

1967 ◽  
Vol 45 (5) ◽  
pp. 1755-1769 ◽  
Author(s):  
I. B. McDiarmid ◽  
E. E. Budzinski ◽  
B. A. Whalen ◽  
N. Sckopke
Keyword(s):  
Geomagnetic Field ◽  
Pitch Angle ◽  
Angular Distributions ◽  
Intensity Increase ◽  
Ionospheric Current ◽  
Atmospheric Scattering ◽  
Auroral Substorms ◽  
Electron Intensity ◽  
Upward Moving ◽  
Particle Intensity

Electron angular distributions obtained from three rocket flights during auroral substorms are described. Pitch-angle distributions of the incident electrons vary from isotropic to strongly peaked at pitch angles near 90°. Isotropic distributions are sometimes maintained for times at least of the order of minutes with very little change in intensity. When an anisotropic distribution persists for some time, the particle intensity is usually observed to decay.Following an intensity increase the angular distribution generally becomes more isotropic. The degree of isotropy attained following an intensity increase does not appear to depend on the magnitude of the increase but rather on the degree of isotropy before the increase.The intensity of upward moving electrons (pitch angles 90–180°) can in most cases be accounted for by atmospheric scattering and mirroring in the undisturbed geomagnetic field. A few cases are observed in which the electron intensity in the pitch-angle range 90–180° is probably larger than can be accounted for by normal scattering and mirroring. The effect of an ionospheric current on the intensity of upward moving electrons is considered.

scholarly journals Excitation And Ionization By Auroral Protons

1966 ◽  
Vol 19 (3) ◽  
pp. 309 ◽  
Keyword(s):  
Magnetic Field ◽  
Energy Range ◽  
Pitch Angle ◽  
Proton Energy ◽  
Ionization Rate ◽  
Energy Spectra ◽  
Proton Fluxes ◽  
Atmospheric Ionization ◽  
The Magnetic Field

Height distributions are presented for the atmospheric ionization rate and Balmer radiation resulting from precipitation of auroral protons. These results have been computed assuming proton fluxes with several different energy spectra and pitch-angle distributions about the magnetic field, the total proton energy range being restricted to 1-1000 keY.

MEASUREMENTS OF SPECTRAL AND ANGULAR DISTRIBUTIONS OF SECONDARY GAMMA-RAYS IN MATTER

1955 ◽  
Vol 33 (2) ◽  
pp. 96-109 ◽  
Author(s):  
G. N. Whyte
Keyword(s):  
Gamma Rays ◽  
Pulse Height ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Barrier Thickness ◽  
Crystal Spectrometer ◽  
Theoretical Predictions ◽  
The Face ◽  
Concrete Barrier ◽  
Secondary Gamma Radiation

The distribution in energy and angle of the secondary gamma radiation emerging from the face of a concrete barrier containing a point source of cobalt-60 has been measured as a function of barrier thickness. Results on energy spectra and angular distributions are presented, and some of their features are compared with theoretical predictions. The operation of the two-crystal spectrometer and the photographic system for recording pulse-height distributions are described in some detail.

scholarly journals Auroral ionospheric E region parameters obtained from satellite-based far ultraviolet and ground-based ionosonde observations: Effects of proton precipitation

2019 ◽  
Author(s):  
Harold K. Knight
Keyword(s):  
Remote Sensing ◽  
Optical Emission ◽  
Electron Precipitation ◽  
E Region ◽  
Emission Models ◽  
Proton Precipitation ◽  
Far Ultraviolet ◽  
Proton Aurora ◽  
Remote Sensing Methods

Abstract. Coincident auroral far ultraviolet (FUV) and ground-based ionosonde observations are compared for the purpose of determining whether auroral FUV remote sensing algorithms that assume pure electron precipitation are biased in the presence of proton precipitation. Auroral particle transport and optical emission models, such as the Boltzmann 3-Constituent (B3C) model, predict that maximum E region electron density (NmE) values derived from auroral Lyman-Birge-Hopfield (LBH) emission assuming electron precipitation will be biased high by up to ~ 20 % for pure proton aurora, while comparisons between LBH radiances and radiances derived from in situ particle flux observations (i.e., Knight et al., 2008, 2012) indicate that the bias associated with proton aurora should be much larger. Surprisingly, in the comparisons with ionosonde observations described here, no bias associated with proton aurora is found in FUV-derived auroral NmE, which means that auroral FUV remote sensing methods for NmE are more accurate in the presence of proton precipitation than was suggested in the aforementioned earlier works. Possible explanations for the discrepancy with the earlier results are discussed.

A STUDY OF THE Be9(He3, n)C11 REACTION

1963 ◽  
Vol 41 (7) ◽  
pp. 1036-1046 ◽  
Author(s):  
L. van der Zwan ◽  
A. T. Stewart ◽  
J. Y. Park ◽  
E. Merzbacher
Keyword(s):  
Compound Nucleus ◽  
Cross Sections ◽  
Interaction Mechanism ◽  
Direct Interaction ◽  
Particle Energy ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Proton Recoil ◽  
The Cross ◽  
Photographic Emulsions

The energy spectra and angular distributions of the emergent neutrons from the Be9(He3, n)C11 reaction have been obtained for an incident He3-particle energy of 2 Mev with the technique of observing proton recoil in photographic emulsions. The cross sections were normalized to Be9(He3, p)B11 data observed simultaneously at 90° to the beam. The lack of similarity in the (He3, n) and (He3, p) mirror reactions to some residual states suggests a direct interaction mechanism rather than compound nucleus. An attempt to analyze some of the data in terms of double particle stripping has been made.

scholarly journals Nuclear disintegrations produced by cosmic rays

1949 ◽  
Vol 196 (1046) ◽  
pp. 325-343 ◽  
Keyword(s):  
Cosmic Radiation ◽  
High Energy ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Excitation Energies ◽  
Wide Range ◽  
High Energy Tail ◽  
Energy And Angular Distributions ◽  
Photographic Emulsions ◽  
Α Particles

Measurements have been made on the energy and angular distributions of the charged particles from disintegration ‘stars’ produced in the silver and bromine nuclei of photographic emulsions exposed to cosmic radiation. The observations extended over a wide range of excitation energies (100 to 700 MeV). The energy spectra and angular distributions of the protons can be explained in all cases by simple evaporation theory. This energy distribution shows also a high-energy tail consisting of direct knock-on protons and slow mesons. At high excitation energies the α-particles exhibit collimation effects which are probably due to localized ‘boiling’ or a form of fission.

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