Active experiments in space in conjunction with Skylab

Two papers are presented which relate to the Skylab barium shaped charge experiments. The first describes the L=6.6 OOSIK barium plasma injection experiment and magnetic storm of March 7, 1972. Rocket payload, instrumentation, data reduction methods, geophysical environment at the time of the experiment, and results are given. The second paper presents the observation of an auroral Birkeland current which developed from the distortion of a barium plasma jet during the above experiment

Rapid Fluctuations in Earth-Currents at College

An unusual type of earth-current variation is regularly observed in the College records. The phenomena consist of more or less regular fluctuations with range from a few mv/km to more than 1000 mv/km, and periods ranging upwards from 6 seconds. The fluctuations may continue from a few minutes to several hours. They have a strong diurnal variation at College with a broad maximum at 0600 local time. The fluctuations also occur at a site about 100 km southeast of College, but are not observed at Barrow« Thus these rapid fluctuations display characteristics quite different from the previously classified magnetic and earth-current continuous pulsations, pc's, and train pulsations, pt's. Special equipment was devised to count and record the period of the fluctuations on a continuous basis. Typical rapid, fluctuation, traces.and charts showing their activity patterns are presented.This research is sponsored by the Geophysics Research Directorate, Air Force Cambridge Research Center, Air Research and Development Command under Contract No. AF 19(604)-3075 and by a grant from the National Science Foundation.Abstract -- Introduction -- Equipment : Geographic location of electrode field ; Stray electric fields ; Electrodes ; Lines ; Recorders ; Cycle counting equipment -- Records and Scaling : Rapid fluctuation records ; Rapid fluctuation at College - selected days ; Rapid fluctuation activity - February 1958 -- Diurnal variation in rapid fluctuation -- Diurnal variation in amplitude and frequency activity ; Rapid fluctuation frequency and period ; Rapid fluctuations at College and at Barrow -- Discussion : Comparison of earth-current rapid fluctuations with geomagnetic pulsations ; Comparison with other earth-current pulsation studies ; Diurnal Variation in amplitude and fluctuation frequency activity at College ; Generation of earth-current rapid fluctuation -- Summary -- Bibliography -- FiguresYe

Active experiments using rocket-borne shaped charge barium releases

A reliable payload system and scaled down shaped charges were developed for carrying out experiments in solar-terrestrial magnetospheric physics. Four Nike-Tomahawk flights with apogees near 450 km were conducted to investigate magnetospheric electric fields, and two Taurus-Tomahawk rockets were flown in experiments on the auroral acceleration process in discrete auroras. In addition, a radial shaped charge was designed for plasma perturbation experiments

AMPS definition study on Optical Band Imager and Photometer System (OBIPS)

A study was conducted to define the characteristics of a modular optical diagnostic system (OBIPS) for AMPS, to provide input to Phase B studies, and to give information useful for experiment planning and design of other instrumentation. The system described consists of visual and UV-band imagers and visual and UV-band photometers; of these the imagers are most important because of their ability to measure intensity as a function of two spatial dimensions and time with high resolution. The various subsystems of OBIPS are in themselves modular with modules having a high degree of interchangeability for versatility, economy, and redundancy

Neutral winds above 200Km at high latitudes

Motion from multiple chemical releases between 200 and 300 km from 15 rockets launched from 4 high latitude locations are analyzed. The observations in the evening and midnight hours at magnetic altitudes or = 65 deg suggest that in these regions ion drag is the dominant force in driving neutral winds between 200 and 300 km. This conclusion is based on both the agreement between ion and neutral drift directions, and the fact that there are distinct changes in the wind associated with (a) the reversal in east-west ion drift at the Harang discontinuity, and (b) the transition from auroral belt, sunward ion drift and polar cap, anti-solar ion drift

NUV/Blue spectral observations of sprites in the 320-460 nm region: N2{\mathrm N_2} (2PG) Emissions

A near-ultraviolet (NUV) spectrograph (320-460 nm) was flown on the EXL98 aircraft sprite observation campaign during July 1998. In this wavelength range video rate (60 fields/sec) spectrographic observations found the NUV/blue emissions to be predominantly N2 (2PG). The negligible level of N2+ (1NG) present in the spectrum is confirmed by observations of a co-aligned, narrowly filtered 427.8 nm imager and is in agreement with previous ground-based filtered photometer observations. The synthetic spectral fit to the observations indicates a characteristic energy of ~1.8 eV, in agreement with our other NUV observations.Comment: 7 pages, 2 figures, 1 table, JGR Space Physics "Effects of Thunderstorms and Lightning in the Upper Atmosphere" Special Sectio

Comparison of NEXRAD-Based and Observed Rainfall Data and TOPMODEL Simulations, McTier Creek Watershed, South Carolina

2012 S.C. Water Resources Conference - Exploring Opportunities for Collaborative Water Research, Policy and Managemen

Apokamps produced by repetitive discharges in air

New experimental and computational data on apokamps produced by repetitive discharges in air, including a detailed description of the research techniques used, are presented. It has been shown that plasma bullets–streamers in apokamps at low frequencies could start not only from the bright offshoot but also directly from the discharge channel. The experimental and computational data demonstrate that the visual color of apokamp changes from blue to red as the intensity ratio of the second to the first positive nitrogen system decreases with the decreasing pressure

Convection and electrodynamic signatures in the vicinity of a Sun-aligned arc: Results from the Polar Acceleration Regions and Convection Study (Polar ARCS)

An experimental campaign designed to study high-latitude auroral arcs was conducted in Sondre Stromfjord, Greenland, on February 26, 1987. The Polar Acceleration Regions and Convection Study (Polar ARCS) consisted of a coordinated set of ground-based, airborne, and sounding rocket measurements of a weak, sun-aligned arc system within the duskside polar cap. A rocket-borne barium release experiment, two DMSP satellite overflights, all-sky photography, and incoherent scatter radar measurements provided information on the large-scale plasma convection over the polar cap region while a second rocket instrumented with a DC magnetometer, Langmuir and electric field probes, and an electron spectrometer provided measurements of small-scale electrodynamics. The large-scale data indicate that small, sun-aligned precipitation events formed within a region of antisunward convection between the duskside auroral oval and a large sun-aligned arc further poleward. This convection signature, used to assess the relationship of the sun-aligned arc to the large-scale magnetospheric configuration, is found to be consistent with either a model in which the arc formed on open field lines on the dusk side of a bifurcated polar cap or on closed field lines threading an expanded low-latitude boundary layer, but not a model in which the polar cap arc field lines map to an expanded plasma sheet. The antisunward convection signature may also be explained by a model in which the polar cap arc formed on long field lines recently reconnected through a highly skewed plasma sheet. The small-scale measurements indicate the rocket passed through three narrow (less than 20 km) regions of low-energy (less than 100 eV) electron precipitation in which the electric and magnetic field perturbations were well correlated. These precipitation events are shown to be associated with regions of downward Poynting flux and small-scale upward and downward field-aligned currents of 1-2 micro-A/sq m. The paired field-aligned currents are associated with velocity shears (higher and lower speed streams) embedded in the region of antisunward flow

Investigation of initiation of gigantic jets connecting thunderclouds to the ionosphere

The initiation of giant electrical discharges called as "gigantic jets" connecting thunderclouds to the ionosphere is investigated by numerical simulation method in this paper. Using similarity relations, the triggering conditions of streamer formation in laboratory situations are extended to form a criterion of initiation of gigantic jets. The energy source causing a gigantic jet is considered due to the quasi-electrostatic field generated by thunderclouds. The electron dynamics from ionization threshold to streamer initiation are simulated by the Monte Carlo technique. It is found that gigantic jets are initiated at a height of ~18-24 km. This is in agreement with the observations. The method presented in this paper could be also applied to the analysis of the initiation of other discharges such as blue jets and red sprites.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France