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Solar wind electron and ion distribution functions measured simultaneously with or close to times of intense electrostatic fluctuations are subjected to a linear Vlasov stability analysis. Although all distributions tested were found to be stable, the analysis suggests that the ion beam instability is the most likely source of the fluctuations.
The soft particle spectrometer on the Isis 2 spacecraft occasionally observes fluxes of ions moving upward out of the ionosphere in the vicinity of the auroral oval. These ion fluxes are characterized by a sharp pitch angle distribution usually peaked at an angle somewhat greater than 90 deg, indicative of particles heated to a large transverse temperature in a narrow range below the spacecraft. The observations are interpreted in terms of electrostatic ion cyclotron waves, which heat the ions to superthermal energies transverse to the earth's magnetic field. When the transverse energy increases, the repulsive force of the earth's magnetic field, proportional to the particle magnetic moment, repels the particles away from the earth.
Capacitive electrostatic transducer (ESAT) measures absolute displacement amplitudes of ultrasonic waves in liquids, and may be used as calibrator for other transducers or as probe for nondestructive study and characterization of materials. ESAT consists of thin conductive membrane stretched over metallic housing. Ultrasonic waves incident on membrane cause it to vibrate and generate signal proportional to wave amplitude. Entire assembly is sealed for immersion in liquid.
The electrostatic forming of antenna and reflector surfaces through the controlled deformation of a reflective membrane is described.
The two problems of enhanced electrostatic discharge (ESD) and contamination are discussed. It is shown that there is a synergistic relationship between them such that one enhances the probability of occurance of the other. The action of both provides substantially more deleterious affects than the effects of both separately. Mechanisms for such a relationship are discussed as well as application to large advanced technology systems.
An introduction to the theory of corona discharge and electrostatic phenomena is presented. The theory is mainly qualitative so that workers in the field should not have to go outside this manual for an understanding of the relevant phenomena. Some of the problems that may occur with the space shuttle in regard to electrical discharge are discussed.
The analysis deals with electron distribution functions constructed from ISEE-1 dayside observations of low-energy magnetospheric electrons at low latitudes. The discussion covers some examples corresponding to three distinct types of odd half harmonic electrostatic emissions, observed in the plasma wave experiment on ISEE-1, which occur between the electron cyclotron frequency and the upper hybrid frequency.
A synoptic study of electric wave, magnetometer, and plasma data from Imp 6 has been carried out for times when banded electrostatic waves are observed between harmonics of the electron gyrofrequency in the earth's outer magnetosphere. Four separate classes of such waves have previously been identified by us. The spatial and temporal occurrences of waves in each class are summarized here, as are correlations of occurrence with geomagnetic activity. Most importantly, associations between the observations of waves of different classes and the relative portions of cold and hot electrons present at the position of the spacecraft are established. The cold to hot ratio varies in accordance with the predictions of our previous theoretical work, which models the emission as arising unstably from a hot loss cone distribution existing simultaneously with a cold isotropic electron component. Finally, evidence for the signature of the loss cone is sought in the plasma data.
Large-scale turbulence transverse to a uniform dc magnetic field is considered from the point of view of a two-fluid model of an electrostatic plasma of variable density. An approximation motivated by 'geostrophic' techniques of dynamic meteorology is introduced. It is argued that the inverse cascade phenomenon should persist in the presence of variable pressure and density.
The physics and equations used in the proposed electrostatic model of a quiet auroral arc are discussed. The procedure for obtaining approximate solutions of Poisson's equation coupled to ionosphere current conservation is given. A comparison with a specific discrete auroral arc as seen from the auroral satellite S3-3 is presented.
A theory of the ion heating due to electrostatic ion cyclotron (EIC) waves in the auroral zone is presented. Due to the slowly convecting nature of the EIC mode, quasi-linear plateau formation cannot stabilize the waves, and growth occurs until the nonlinear mechanisms of ion resonance broadening and electron trapping provide saturation. The large amplitude and coherent nature of the resulting wave imply that quasi-linear theory provides only a lower limit to the ion heating. An upper bound on the heating rate is derived using a time-average model of ion dynamics in the coherent waves. The effects of ion heating in the presence of the magnetic gradient force and parallel electric fields are considered, with the result that perpendicular energies over 100 eV are easily attainable from a 1 eV source plasma. Perpendicular heating in the absence of a parallel electric field yields conical ion distributions, which in the presence of an electric field become field-aligned beams.
A comprehensive discussion and calculation of electrical torques on an electrostatic gyro as they relate to the gyroscope experiment to test general relativity is presented. Drift rates were computed for some typical state of the art rotors, including higher harmonics in the rotor shape. The effect of orbital averaging of gravity gradient forces, roll averaging of torques, and the effect of spin averaging on the effective shape of the rotor were considered. The electrical torques are reduced sufficiently in a low g environment to permit a measurement of the relativistic drifts predicted by general relativity.
The electrostatic cyclotron and ion acoustic instabilities in a plasma driven by a combined heat flux and current were investigated. The minimum critical heat conduction speed (above which the plasma is unstable) is given as a function of the ratio of electron to ion temperatures.
Electrostatic bonding of thin cover glass to thin solar cells was researched. Silicon solar cells, wafers, and Corning 7070 glass of from about 0.002" to about 0.003" in thickness were used in the investigation to establish optimum parameters for producing mechanically acceptable bonds while minimizing thermal stresses and resultant solar cell electrical parameter degradation.
A worst case assessment was performed on the Command Data System (CDS) multilayer printed circuit board and an output power transformer module in the power subsystem. An estimate of the Jovian environment during the 35 hour orbit insertion was supplied by JPL and used as an input to calculate the electron transport into the Galileo components. A radiation shielding analysis computer code, CHARGE, calculated the electron transport deposition trapped in the anticipated sensitive areas of the multilayer board and transformer module. Based on these trapped charge calculations electric fields were calculated between the identified isolated areas and the spacecraft ground. The results of the assessment of electrostatic discharge (DSD) in the CDS multilayer printed circuit board indicate that the probability of ESD in the FR4 is low. The probability of ESD in the components attached to the multilayer board, however, is uncertain based on a lack of prior experimental data.
Electrostatic bonding (ESB) of thin (3 mil) Corning 7070 cover glasses to Ta2O5 AR-coated thin (2 mil) silicon wafers and solar cells is investigated. An experimental program was conducted to establish the effects of variations in pressure, voltage, temperature, time, Ta2O5 thickness, and various prebond glass treatments. Flat wafers without contact grids were used to study the basic effects for bonding to semiconductor surfaces typical of solar cells. Solar cells with three different grid patterns were used to determine additional requirements caused by the raised metallic contacts.
The development of an electrostatic membrane antenna for large space structure applications is discussed. Problems encountered in fabricating 4.88 m (16 foot) diameter thin film membranes are addressed. The development of a test fixture for evaluating the membranes and the comparison of surface measurement systems are also discussed.
A possible mechanism is presented for the generation of large-amplitude temporal fluctuations in the structure of the electron energization region associated with auroral arcs. The mechanism is based on the observation that the auroral arc system resembles a laboratory circuit consisting of the series connection of battery, resistance and a forward biased diode containing collisionless plasma in which large-amplitude relaxation oscillations are sometimes observed to be superimposed on the steady-state current. It is shown that in both the laboratory and auroral systems, in which a localized auroral arc dynamo, the ionosphere and the electron energization region are involved, the oscillations are controlled by the times for ions and electrons to traverse the acceleration region, which also characterize the low- and high-frequency structure of the fluctuating waveform. It is demonstrated that a plausible one-dimensional double-layer model of the auroral arc acceleration region exhibits the dynamic negative resistance necessary for the generation of oscillations by the present mechanism. Finally, consideration is given to two kinds of auroral phenomena which might be associated with the mechanism: the 10-Hz quasi-periodic flickering aurora and 10-Hz modulations in the intensity of electrostatic hydrogen cyclotron waves.