Showing papers in "Planetary and Space Science in 1976"

TL;DR: In this paper, the authors analyzed 400 hours of continuous broadband data obtained by the OGO 3 satellite to provide a statistically accurate description of band-limited (magnetospheric) chorus and concluded that most magnetospheric chorus consists of rising emissions which are probably generated by gyroresonant electrons slightly off the equator.

TL;DR: In this paper, the signatures of multiple-expansion-phase substorm onsets in night-time magnetograms as well as in recordings of auroral activity and energetic electron precipitation were examined.

TL;DR: In this paper, the authors examined the onset times of three substorm events which were already defined by various methods other than the low-latitude Pi2 method and determined other evident substorm onsets are clearly determined with Pi2 onsets for all the three events by examining only the H -component of rapid-run magnetogram from a single lowlatitude station in the dark hemisphere.

TL;DR: In this paper, a 2 MV Van De Graaff dust accelerator was used to measure the spectral distribution of the light emitted during an impact, which was then used to estimate the amount of material vaporized during the impact.

TL;DR: In this article, the motion of charged particles is examined in the case of a homogeneous magnetic field B together with an orthogonal electric field E, which has a gradient ▽E parallel to B. If B 2 q 2 m 2 − q▽E m > 0, the particles drift at right angles to E and B with a modified gyrofrequency and produce a current in that direction.

TL;DR: Theoretical electron density profiles are calculated for the topside ionosphere to determine the major factors controlling the profile shape as mentioned in this paper, including mean temperature, the vertical temperature gradient and the O + H + ion transition height.

TL;DR: In this article, the authors examined the correlation between the onset of the auroral arc and the Pi2 magnetic pulsation in low latitudes and found that the low-latitude Pi2 occurs almost simultaneously with the sudden brightening of the arc.

TL;DR: The relationship between the relativistic electron bursts (0.3 ∼ 1.0 MeV) observed in the magnetotail at X = −20 ∼ −30 R e and the evolution of the structure of the magnetosphere during substorms is investigated in this article.

TL;DR: In this article, the longitudinal phase variation of Pc3-4 micropulsations has been investigated using data from three stations at geomagnetic latitude ∼54°, in the British Isles.

TL;DR: In this article, an approximate expression for the marginally stable distribution was obtained for a spin-aligned dipole field, where the plasma content of a unit magnetic flux tube is a decreasing function of distance from the spin axis.

TL;DR: In this article, daily measurements of the intensity distribution of the Sun's white-light corona over the height range 1.1-2.7 were used to confirm the cone-of-avoidance model for M-regions and reinforce the postulate that high speed streams in the solar wind originate from coronal holes.

TL;DR: In this article, a numerical model of the diurnal transport of water across the Martian surface is developed, where the atmospheric boundary layer is modeled in terms of local radiative-convective processes, and radiative effects of ice fogs near the surface are included.

TL;DR: In this paper, a rocket experiment was conducted which measured the infrared bands of the excited hydroxyl radical in the night airglow and the OH emission was found in a layer centered at 87 km having a half-width of 6 km and a total emission of 1.1 MR.

TL;DR: In this article, the spectral range of the Schumann-Runge bands of molecular oxygen was analyzed between 1750 and 2050 A and the variation of the absorption cross section with temperature was taken into account and it was shown that average O2 absorption cross sections cannot lead to correct photodissociation coefficients.

TL;DR: In the case of the Moon, the magnetic field is briefly but strongly enhanced as the large partially ionized cometary atmosphere is compressed against the planetary surface as discussed by the authors, and then the solid part of the comet collides with the surface.

TL;DR: In this paper, a one-year set of Lyman-alpha airglow data measured in the local zenith at altitudes from 400 to 1100 km by a UV photometer aboard OGO-6 was analyzed.

TL;DR: In this paper, it was shown that the geomagnetic tail is a good resonator for the hydromagnetic disturbances in the solar wind, and that the flapping motions result from fluctuations in the interplanetary magnetic field, especially Alfvenic fluctuations.

TL;DR: In this article, the authors considered the generation of low-frequency waves in the solar wind by the flux of protons accelerated in the magnetosheath and showed that the growth rate of waves is maximal when the angle θ between the direction of the interplanetary magnetic field and the front of the bow shock is not equal π2.

TL;DR: In this article, the mutual neutralization rates for the water cluster ion H3O+ · (H2O)3 with a mixture of several negative ions which are known to exist in the D region were determined.

TL;DR: Using Boltzmann-Fokker-Planck methods and the diffusion approximation, this paper derived coupled non-linear equations for the first two angular moments of the electron distribution function in the Earth's ionosphere.

TL;DR: In this paper, nonthermal escape of oxygen by recombination of exospheric O_2^+ combined with diffusive separation of gases at lower altitude provides a mechanism through which the Martian atmosphere may be enriched in O(18)O relative to O(16)O.

TL;DR: In this paper, the authors examined the timing of the plasma-sheet thinning relative to the onset of the expansion phase of substorms and found that the thinning is significantly dependent on the distance.

TL;DR: Theoretical calculations of the equilibrium photoelectron fluxes in the upper atmosphere are reported in this article, which employ an accurate description of the photo-electron production processes and take explicit account of the discrete nature of the electron energy losses.

TL;DR: In this article, neutral composition data obtained by the gas analyzer aboard the satellite ESRO 4 were investigated for a period of increasing magnetic activity, and the prominent feature observed is the development of localized disturbance zones in the high and mid-latitude regions which show a significant enhancement in argon and nitrogen densities and a simultaneous decrease in helium densities.

TL;DR: In this paper, a survey of low-frequency pulsation activity in the outer regions of the geomagnetic field is presented, showing that this phenomenon is relatively common in the 8-12 Re, geocentric distance range near dusk.

TL;DR: In this paper, the time-dependent O+ continuity equation is solved numerically, including the effects of production by photoionization, loss by charge exchange and transport by diffusion, neutral wind and E × B drift.

TL;DR: In this paper, the location of field-aligned currents in the evening sector with respect to the auroral electrojets is examined using the TRIAD satellite data and the simultaneous ground magnetometer data from along the Alaska meridian.

TL;DR: In this paper, the authors presented energy spectra and angular and spatial distributions of electron fluxes in the ionosphere resulting from precipitation of monoenergetic (E = 25, 50, and 100 eV) electrons.

TL;DR: In this paper, electron density observations made in the ionosphere by the Ariel 4 and Isis 2 satellites are examined in conjunction with results obtained by Explorer 45 when it traversed the near-equatorial plasmapause with one hour (both UT and MLT) of the Ariel and Isis traversals of the same L coordinate.

TL;DR: In this paper, the authors measured the diurnal and seasonal changes in temperature from 75°S to 85°N near solar minimum by fitting theoretical models to 60,000 observed electron density profiles, at heights of 400-1000 km.