Helium isotopes escape mechanism from earth atmosphere related to polar wind ionospheric plasma flow from earth

The polar wind and the terrestrial helium budget

A study has been made of electron density and total electron content in tubes of force near the knee in magnetospheric ionization. It was based on whistler observations made at Eights, Antarctica, in July and August 1963, under conditions of steady, moderate geomagnetic agitation (Kp = 2–4). During the period 0100–0400 LT, the electron density near the equatorial plane at a geocentric distance of 4 RE drops a factor of 30–100 within a distance of less than 0.15 RE. The corresponding change in tube content above 1 cm2 at 1000 km is a factor of about 10 within less than a degree of latitude. The afternoon profiles are generally similar to the postmidnight results. In the afternoon the profiles are often well defined outside the knee, falling smoothly to about 1 el/cm3 at 7 RE. Both the equatorial and tube content profiles show a definite repeatability between observations at a given local time and under conditions of moderate, steady geomagnetic agitation. Diurnal effects are evident, with amplitude differing from point to point on the profiles. The problem of the field-line distribution of ionization has been studied with a view to minimizing error in the profiles. Experimental and theoretical support has been found for using a diffusive-equilibrium distribution along the field lines inside the knee and a ‘collisionless’ model, behaving approximately as Ne ∝ R−4, along the field lines outside the knee. A study of error shows that the uncertainty in individual points on the knee profiles is everywhere less than a factor of ±2, and on the content profiles less than a factor of ±1.5.

Whistler studies of the plasmapause in the magnetosphere: 2. Electron density and total tube electron content near the knee in magnetospheric ionization

At the present time the existing satellite observations of ULF waves suggest that the level of geomagnetic activity controls the types of waves which occur within the magnetosphere. Consequently, we consider separately quiet times, times of magnetospheric substorms, and times of magnetic storms. Within each of these categories, there are distinctly different wave modes distinguished by their polarization: either transverse or parallel to the ambient field. In addition, these wave phenomena occur in distinct frequency bands. In terms of the standard nomenclature of ground micropulsation studies ULF wave types observed in the magnetosphere include quiet time transverse - Pc 1, Pc 3, Pc 4, Pc 5; quiet time compressional - Pc 1 and Pi 1; substorm compressional Pi 1 and Pi 2; storm transverse - Pc 1; storm compressional Pc 4, 5.

Fluctuating magnetic fields in the magnetosphere. II - ULF waves.

Thermal hydrogen and helium ion distribution in magnetoionosphere - OGO-A positive ion spectrometer

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Positive ion composition in the magnetoionosphere obtained from the Ogo‐A satellite

The electrostatic analyzer aboard Imp 7 examined energy spectra of positive ions in certain streaming plasmas adjacent to the plasma sheet and within the geomagnetic tail at geocentric radial distances of about 35 R-E, revealing minor, though often persistent, secondary maxima of intensities with energy per unit charge a factor of 16 greater than that of the maxima corresponding to the dominant H(+) ions The secondary maximum at higher E/Q was identified as a small flux of singly ionized atomic oxygen O(+), from the ionosphere O(+) fluxes in the geomagnetic tail were about 10 to the 5th/(sq cm s) and imply O(+) upward fluxes in the upper ionosphere of about 10 to the 8th/(sq cm s) The kinetic energy of the oxygen ions is about 1-5 keV, while estimates of the global escape of the ions are about 3 x 10 to the 6th kg/yr

Observations of atomic oxygen (O+) in the Earth's magnetotail

Evidence is presented to support the hypothesis that the low frequency cutoff of a VLF noise band observed by the Alouette 1 satellite is due to a plasma resonance (the lower hybrid resonance) which defines a cutoff frequency for propagation transverse to the earth's field. If this hypothesis is accepted, the observations of this cutoff frequency by the satellite's VLF receiver, and simultaneous measurements of the electron plasma frequency by the topside sounder, can be used to determine an effective mean mass for the ions in the ambient plasma. The values, together with the scale height measured from the electron density profiles, set limits on the ion composition and temperature. The main support for the hybrid resonance hypothesis lies in the plausibility of the temperature and ion mass information that is derived using this interpretation and the agreement between this information and the results of other workers. In general, is found to be larger during the day than at night and to increase with latitude. In polar regions ranges from about 7 at midnight to about 13 at noon; at midnight the composition of the polar ionosphere at 1000 km is more than 60% O+, whereas at noon it is about 95% O+. At middle latitudes, L = 2 to 3, ranges from 1.8 to as high as 7. For low latitudes, L < 2, the lowest observed values of of 1.3 require that the H+ concentration be greater than 68%. An effective ionospheric temperature of about 1200°K is determined for middle latitudes, increasing to high values for high latitudes. A marked diurnal variation of temperature is found at high latitudes.

Ion composition and temperatures at 1000 km as deduced from simultaneous observations of a VLF plasma resonance and topside sounding data from the Alouette 1 satellite

The successful launch of the Alouette II satellite is announced. A brief description is given of the experiments on board and some early indications of the results obtained are presented.

R. E. Barrington

Papers

Ion composition and temperatures at 1000 km as deduced from simultaneous observations of a VLF plasma resonance and topside sounding data from the Alouette 1 satellite

The Alouette II satellite.

Ion composition and temperature at 1000 km as deduced from VLF resonances and topside ionograms