Charged Satellite Research Articles

Multipolar x-ray diffractionstudy of the canted magnetic structure of TbMg

Earlier neutron powder diffraction measurements on the CsClcompound TbMg showed that a canted magnetic structure isstabilized at T = 4.2 K. This structure mixes ferromagneticand antiferromagnetic, ⟨½ 0 0⟩, components. Accounting for the anisotropy, several consistent models ofstructures could be proposed. In order to identify the bestone, we performed x-ray diffraction measurements on a singlecrystal. A set of charge satellites originating from multipolar 4fscattering and related to the ⟨½ 0 0⟩wavevectors were observed. Analysing the experimental data, withinthe framework recently proposed for multipolar scattering in cubicsystems, a model is selected for the magnetic structure of TbMg.

Hydrodynamic Approach to Modeling the Thermal Plasma Distribution around a Moving Charged Satellite

The electric field distribution around a charged satellite in a rarefied magnetospheric plasma influences greatly the densities and trajectories of particles measured by onboard instruments. The simulation of macroparameters of thermal plasma near the moving charged satellite, which is necessary for correction of experimental measurements, encounters considerable computational difficulties. In this work, two three-dimensional models of the electric field distribution around the satellite are considered under the conditions when the Debye length is comparable to the geometrical size of the spacecraft. In the first model a system of hydrodynamic equations of continuity and motion was used, which was solved jointly with the Poisson equation. In the second model the hydrodynamic equation of motion was used for analyzing the motion of large particles by means of the method of particles in a cell. The numerical algorithms and the results of calculations of the potential near the satellite, as well as the distributions of densities of electrons and ions and of volume charge, are considered. The results of test calculations for some situations in the ambient plasma are presented, and the influence of the spatial electric field distribution on the thermal plasma measurements is considered.

The onset of coulomb explosions in polyatomic molecules

With the development of high intensity femtosecond lasers, the ionisation and dissociation dynamics of molecules has become an area of considerable interest. Using the technique of femtosecond laser mass spectrometry (FLMS), the molecules carbon disulphide, pyrimidine, toluene, cyclohexanone and benzaldehyde are studied with pulse widths of 50 fs in the near infrared (IR) wavelength region (790 nm). Results are presented and contrasted for laser beam intensities around 10(15) and 10(16) W cm(-2). For the lower intensities, the mass spectra yield dominant singly charged parent ions. Additionally, the appearance of doubly charged parent ions is evident for carbon disulphide, toluene and benzaldehyde with envelopes of doubly charged satellite species existing in these local regions. Carbon disulphide also reveals a small triply charged component. Such atomic-like features are thought to be a strong fingerprint of FLMS at these intensities. However, upon increasing the laser intensity to approximately 10(16) W cm(-2), parent ion dominance decreases and the appearance of multiply charged atomic species occurs, particularly carbon. This phenomenon has been attributed to Coulomb explosions in which the fast absorption of many photons may produce transient highly ionised parent species which can subsequently blow apart. Copyright 1999 John Wiley & Sons, Ltd.

The effect of photoelectrons on boom‐satellite potential differences during electron beam ejection

Data taken on the SCATHA satellite at geosynchronous altitudes during periods of electron beam ejection in sunlight showed that the potential difference between an electrically isolated boom and the satellite main body was a function of beam current, energy, and boom‐sun angle. The potential difference decreased as the boom area illuminated by the sun increased; the maximum and minimum potential differences were measured when minimum and maximum boom areas, respectively, were exposed to the sun. It is shown that photoelectrons, created on the boom, could be engulfed in the electrostatic field of the highly charged satellite main body. Theoretical calculations made using a simple current balance model showed that these electrons could provide a substantial discharging current to the main body and cause the observed variations in the potential difference between the main body and the booms.

The Modification of Joint Size-Charge Distribution in Rain. Part II: Computations Involving Partial Coalescence

Raindrop collisional breakup is included in a model of joint size-charge distribution development. Consistent with experimental observations the model includes a finite filament (joining separating drops) that upon rupture produces charged satellite droplets. It is shown that for positive fields, large numbers of small drops carry negative charge, leading to an increasingly negative space charge with fall depth. The model also suggests that larger separated charge exists on the major drop products than previously estimated.

A discussion on orbital analysis - Properties of the upper atmosphere determined from satellite orbits

Irregularities in the Earth’s gravitational potential perturb the orbits of artificial satellites in a great many ways. They cannot, however, change the mean value of the major axis of an orbit, which determines the period of revolution. To change the orbital period a dissipative force is required, such as the drag exerted on the satellite by the Earth’s atmosphere. Solar radiation pressure does not affect the period of a satellite provided the satellite does not cross the shadow cone of the Earth. If the orbit is all in daylight, the effect of the force cancels out after one revolution. If, however, the satellite goes in and out of the Earth’s shadow, and the orbit is not circular, the effect does not cancel out and radiation pressure will cause a change in the period. Atmospheric drag and solar radiation pressure are the only major forces that are known to affect the period of a satellite. Other forces, such as the interaction of an electrically charged satellite with atmospheric ions or with the magnetic field of the Earth, are undoubtedly present, but they are generally quite small. For low-orbiting satellites, with perigees below 300 km, the effect of atmospheric drag on the orbital period is so much larger than that of solar radiation pressure, that the latter can be neglected for all practical purposes. Above 400 km, however, radiation pressure makes itself felt, and above 700 km it may become more important than atmospheric drag. Actually, these figures vary a great deal with the phase of the solar cycle, since the atmosphere expands or contracts with solar activity. At sunspot minimum the effect of radiation pressure becomes comparable with that of atmospheric drag at about 600 km, while at sunspot maximum it does not become so below 1100 km.

Particles trapped in the Potential Well behind a Mesothermally Moving Satellite

The presence of a negative potential valley in the near wake of a negatively charged satellite suggests the existence of a belt filled with oscillating particles.

Hydrogen—Ionized and Otherwise

Editorials1 October 1962Hydrogen—Ionized and OtherwiseJ. R. E.J. R. E.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-57-4-687 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptWhen God made the world he began, presumably, with hydrogen. Hydrogen is the first element in the periodic table and consists of two primary particles: a positively charged nucleus, the proton, and an orbiting negatively charged satellite, the electron. When these two components of the hydrogen atom are separated, the positively charged proton, or hydrogen ion, becomes a sort of chemical "agitator" that arouses a high degree of reactivity and instability among its ionic and molecular neighbors. In the beginning there was chaos and hydrogen, in the end there is—among other results of creation—acid-base balance and the oft-confused physician who...

Effects of the Earth's magnetic field on the orbit of a charged satellite

The changes in the orbital elements of a charged satellite due to the v×B force have been examined. We conclude that the ascending nodes of the Project West Ford dipoles may be detectably perturbed by it.

Author's reply to the Beard-Johnson comments [on “Induction drag on a large negatively charged satellite moving in a magnetic-field-free atmosphere”

Author's reply to the Beard-Johnson comments [on “Induction drag on a large negatively charged satellite moving in a magnetic-field-free atmosphere”

The drag on a charged satellite[: Comment on “Induction drag on a large negatively charged satellite moving in a magnetic-field-free atmosphere” by P. J. Wyatt

The drag on a charged satellite[: Comment on “Induction drag on a large negatively charged satellite moving in a magnetic-field-free atmosphere” by P. J. Wyatt

Induction drag on a large negatively charged satellite moving in a magnetic-field-free ionosphere

An induction drag, experienced by a charged satellite during its traversal of the ionosphere, has been theoretically postulated by several authors. Previous ‘exact’ treatments of the problem are inapplicable to large systems, and the semiempirical approach of Jastrow and Pearse may yield somewhat questionable results. The present description initially considers the satellite as a completely permeable spherical shell of charge, thus avoiding the difficult boundary conditions introduced by the ‘exact’ linearized treatment. The effects of permeability are then shown to be approximately removable by means of an iterative process. A final result, apparently valid to within an order of magnitude, is obtained for the drag force arising solely from electrical effects. Its magnitude is considerably less than that obtained by Jastrow and Pearse.