Observation and explanation of a 0.3% sunward radial streaming of 1 to 5 GV cosmic radiation

Solar Physics - Quiet-time anisotropy data have been obtained by the HEOS-1 spacecraft between December 1968 and April 1970 using an 8-sector analysis of a ?erenkov telescope which has a...     

The lunar atmosphere

In contrast to earth, the atmosphere of the moon is exceedingly tenuous and appears to consist mainly of noble gases. The solar wind impinges on the lunar surface, supplying detectable amounts of helium, neon and ³⁶Ar. Influxes of solar wind protons and carbon and nitrogen ions are significant, but atmospheric gases containing these elements have not been positively identified. Radiogenic ⁴⁰Ar and ²²²Rn produced within the moon have been detected. The present rate of effusion of argon from the moon accounts for about 0.4% of the total production of ⁴⁰Ar due to decay of ⁴⁰K if the average abundance of potassium in the moon is 1000 ppm. Lack of weathering processes in the regolith suggests that most of the atmospheric ⁴⁰Ar originates deep in the lunar interior, perhaps in a partially molten core. If so, other gases may be vented along with the argon.     

Auroral displays near the ‘foot’ of the field line of the ATS-5 satellite

This paper presents a brief summary of an extensive correlative study of ATS-5 particle and magnetic field data with all-sky photographs from Great Whale River which is near the ‘foot’ of the field lines passing through the ATS-5 satellite. In particular, an effort is made to identify specific particle features with specific auroral displays during substorms, such as a westward travelling surge, poleward expansive motion and drifting patches. Some of the important findings are (i) in early evening hours, the first encounter of ATS-5 with hot plasma is associated with the equatorward shift of the diffuse aurora, but not necessarily with westward travelling surges (even when the satellite is embedded in the plasma sheet.) (ii) In the midnight sector, an injection corresponds very well to the initial brightening of an auroral arc. (iii) Specific features of morning sector auroras (for example, drifting patches) are difficult to correlate with specific particle features (gross features, but not specific).Comparing these results with particle data from low-latitude polar orbiting satellites, it is concluded that the plasma sheet near the earthward edge (consisting of plasmas injected during earlier substorms) is little affected during substorms.     

Some consequences of a steady thermal moon

The Moon is represented as an inhomogeneous spherical body in a steady thermal state. Radioactive heat sources are supposed distributed in a manner which is consistent both with the total measured heat flux near the surface and with the broad seismic evidence. Surface concentrations of uranium and thorium are those suggested by the study of Apollo 11 samples. The resultant internal temperature profile allows the details of Sonett's electrical conductivity profile to be understood if it is accepted that the Moon was not cold 4.5 × 10⁹ yr ago. It would appear further that at least one of the maria was formed by the impact of planetesimals.     

The influence of the energy dependence of the diffusion coefficient on the spectrum of the electron component of cosmic rays and the radio background radiation of the galaxy

The diffusion of electrons through interstellar space, and the energy dependence of the diffusion coefficient are considered. Apart from the caseD=const the spectral index for electrons with spectral index γ₀ changes according to γ₀+μ→γ₀+½μ+½→γ₀+1 (D(E)=D₀(E/E₀)^μ) for μ<1; for μ>1 to γ₀+1→γ₀+½μ+½→γ₀+μ. We consider the radio emission spectrum in such a case. From a comparison with observations the limit μ≤0.4 is obtained.     

OnH-functions of radiative transfer

Chandrasekhar'sH-functionH(z) corresponding to the dispersion functionT(z)=| _rs –frs(z)|, where [f _rs (z)] is of rank 1, is obtained in terms of a Cauchy integral whose density functionQ(x, ₁, ₂,...) can be approximated by approximating polynomials (uniformly converging toQ(x)) having their coefficients expressed as known functions of the parameters _r 's. A closed form approximation ofH(z) to a sufficiently high degree of accuracy is then readily available by term by term integration.     

Production and propagation of cosmic ray H2 and He3 nuclei

The results of detailed calculations on the production of H² and He³ nuclei by cosmic ray protons and helium nuclei in interstellar medium are presented. The flux and energy spectra of these nuclei as well as those of cosmic ray H¹ and He⁴ nuclei in the vicinity of the Earth are calculated. For this purpose the source spectra are assumed to be in the form of a power law in total energy per nucleon with an additional velocity dependent term. This spectrum denoted as Fermi Spectrum, is about midway between the power law spectrum in rigidity and in total energy per nucleon. The fluxes are calculated taking into account: (1) energy dependent cross-sections of thirteen nuclear reactions of cosmic ray protons and helium nuclei with interstellar H¹ and He⁴ leading to the production of H² and He³ nuclei, (2) angular distributions and kinematics of these reactions, (3) ionization loss of the primary and secondary nuclei in interstellar medium, (4) elastic collisions of cosmic ray protons and helium nuclei, (5) distributions of cosmic ray path-lengths in in terstellar space as in gaussian and exponential forms, and (6) interplanetary modulation of cosmic rays from the numerical solution of the complete Fokker-Planck equation describing the diffusion, convection and adiabatic deceleration of cosmic ray nuclei in the solar system. On comparing the calculated values of H²/He⁴ and He³/(He³+He⁴) as a function of energy with the observed data of several investigators, it is found that agreement between the calculated values and most of the observed data is obtained on the basis of: (a) source spectrum in the form of Fermi Spectrum, (b) distribution of path-lengths as in the gaussian form with a mean value of 4 g cm^–2 of hydrogen or as in exponential form with leakage path length of 4 g cm^–2.     

An investigation of some large directional discontinuities in the solar wind plasma using multisatellite observations

Eleven large directional discontinuities in the solar wind, simultaneously observed by Explorers 33, 35 and Heos 1 in the period Dec. 1968 to Jan. 1969, have been studied by the triangulation method. Testing the discontinuity normals deduced from the wind speed and timing parameters against those given by the magnetometer observations on different models suggests that 8 were tangential, 2 were rotational while 1 could not be identified. 3 small tangential discontinuities arriving within a period 35 min were also studied and as a result it is suggested that the solar wind remained stratified in separation planes over a distance 0.01 AU during that time. The implication of these results is briefly discussed.     

Hydrogen and helium spectra in large magnetic fields

The energy levels and wave functions of hydrogen and helium atoms in the presence of large (10⁷G) magnetic fields are found by assuming that the eigenvalues and eigenvectors may be approximated by those of a truncated Hamiltonian matrix. In these atoms, fields of this size produce, in addition to the usual Paschen-Back effect, a quadratic Zeeman effect. This contributes an upward shift to the energy of all levels, which at sufficiently high fields dominates the Paschen-Back splitting.The behavior of a number of eigenvalues and wave functions as a function of magnetic field is presented. The effects of the field on the wavelengths and strengths of the components of H and the helium lines 4471, 4026 and 4120 as well as the forbidden 4025 are examined. In hydrogen the lines are split into components attributed to the now nondegenerate transitionsnlm _lnlm_l. In helium forbidden lines are excited, which may develop strengths larger than those of the allowed lines.     

Spherical mhd shock waves under the action of monochromatic radiation

Self-similar MHD shock waves have been studied under the action of monochromatic radiation into a non-uniform stellar atmosphere with a constant intensity on unit area. It has been assumed that the radiation flux moves through the gas. Variation of flow variables have heen shown in tables for two different cases.