Particle Electric Charge Research Articles

Magnetometer networks during the International Magnetosphere Study

The International Magnetospheric Study (IMS) has been organized as an international program for the first extensive attempt to perform coordinated research on well‐defined problems of the terrestrial magnetosphere [Joint COSPAR/IUCSTP Special Study Group for the IMS, 1971,1972;; Roederer, 1976; Manka, 1976]. Over the last decade or more, using instrumented satellites and sophisticated ground‐based observations, we have learned that the space environment surrounding the earth consists of an extremely complex system of electric and magnetic fields and charged particles (Figure 1). However, it may be one of the simpler of the natural plasma systems found among the other planets in the solar system and throughout the universe. As we progress to a deeper physical understanding of the earth's fascinating plasma environment, we will undoubtedly reach better appreciation and comprehension of these other systems. Further, and not to be underestimated, are the contributions that these understandings will make in significant ways to the establishing of more fundamental bases for the environmental processes known to affect complex man‐made technological systems.

A search for fractionally charged particles at the CERN intersecting storage rings

We report final results of a search for fractionally charged particles at the CERN intersecting Storage Rings. Several independent scintillation counter, multiwire proportional chamber (MWPC) telescopes simultaneously sampled c.m. production angles from 0° to 90°. The experiment was sensitive to particles of electric charge in the range 0.1 e < ∣ Q∣ < 0.8 e, with velocities greater than 0.25 c and with masses up to, in principle, 47 GeV/ c 2. No such particles were observed among the products of 1.2 × 10 10 proton-proton interactions at s = 2830 GeV 2. Our cross section limit for the production of quark-antiquark pairs of charge ∣Q∣ = 1 3 e in the reaction pp → ppq q , at s = 2830 GeV 2, is σ ≲ 4 × 10 −35 cm 2 (90% confidence level) for quark masses up to ≈20 GeV/ c 2. For quarks with charge ∣Q∣ = 2 3 e , the corresponding limit is σ ≲ 8 × 10 −35 cm 2, again for quark masses up to ≈20 GeV/ c 2.

New formulation of noise in collision-free systems. III

The problem of velocity fluctuations in collision-free systems is usually solved by introducing the concept of phase-space density and treating the corresponding position and velocity variables as random variables. It is shown that in order to account for density as well as velocity fluctuations the probabilistic content of the analysis must be enlarged and the phase-space density itself must be treated as a random function with position and velocity as parameters. This generalization makes it possible to retain the highly non-linear character of interaction between electric fields and charged particles (space-charge effects) ; consequently the method is particularly welt suited to the treatment of very shallow minima, where the usual perturbation procedures tend to break down. Also the method appears to be capable of extension to the analysis of crosaed-field systems. As an example the analysis of noise in thermionic diodes has been carried out in some detail. The numerical results appear to be in closer...

Performance Characteristics of the Multicyclone Aerosol Sampler

The multicyclone aerosol sampler of Lippmann and Kydonieus has been redesigned for use in underground coal mines. It now includes an intrinsically safe battery-powered brushless dc motor coupled to a vane pump. Particles are collected by seven parallel samplers which surround a common inlet. Six samplers consist of a 10-mm nylon cyclone and a filter in series. Each cyclone operates at a different flow and has a different size cut. The seventh sampler is a filter alone. Analysis of the seven filter samples permits the construction of a size-mass distribution curve describing the airborne aerosol. Cyclone collection efficiencies were determind for aerodynamic particle sizes from 0.3 to 8 microns and for flow rates between 0.9 and 30 liters/min. The effects of particle electric charge, cyclone orientation, aerosol concentration, sample mass collected, and sampling rate pulsations on cyclone collection were also determined.

Runge Solution of the Continuum Equations for Spherical Electrostatic Plasma Probes

An approximate but convergent method is used to determine the electric potential and charged particle density near non-small spherical probes in a weakly ionized continuum plasma. Quantities determined partly by experiment (e, PP' yp) and partly from continuum theory (J +, J _) are introduced into three continuum differential equations which are then solved using Runge's method. The initial conditions must be estimated iteratively until the sheath solution joins smoothly to the quasi-neutral solution. Two different types of solution curves are discussed.

Field-aligned particle currents near an auroral arc

A Nike-Tomahawk rocket equipped to measure electric and magnetic fields and charged particles from a few eV to several hundred keV energy was flown into an auroral band on April 11, 1970. The purpose of this flight was to obtain evidence of the low-energy electrons and protons that constitute a field-aligned sheet current, and also to obtain the magnetic signature of such a current and the electric field in and near the auroral-arc electric current system. Particular attention was given to a sudden increase in the field-aligned current associated with a prior sudden increase in the electric field and a sudden change in the magnetic field, all occurring near the edge of a visual auroral arc. Data obtained are discussed and analyzed; they present an important contribution to the problem of mapping of atmospheric auroral phenomena to the magnetospheric equatorial plane.

Electrostatic Fire Detection

Experimental work was carried out to determine the feasibility of detecting flames by means of an insulated wire grid placed over the entire surveillance area thus eliminating expensive individual detectors. By maintaining the umbrella grid at an electric potential, charged particles and ions are extracted from the flames. As they move toward the grid, they are deposited on the interposing surfaces and their accumulation is detected in the form of an electric current. To eliminate the effect of ambient ions which also act as an electric charge deposited on the same surfaces, as well as large charge accumulations due to the flames, the polarity of the grid potential is switched periodically. It is believed that the system would find applications in one-story residential homes with the grid mounted in the attic or roof. It would be energized only at nighttime because some of the appliances used during the day in a home may trigger the alarm.

Phenomenological Presentation of the Dirac Quantization of Magnetic Charge

The field-dependent difference in phase associated with two paths in an interference experiment employing electrically charged particles of electric charge $e$ is ordinarily proportional to the magnetic flux through a surface bounded by the difference of the paths. If considered as a visible electron-optical fringe displacement, it may be used as a phenomenological support for Dirac's condition $eg=\frac{1}{2}n$, restricting the strength of a magnetic monopole.

The charging and mobility of chain aggregate smoke particles

The fluid drag force and unipolar diffusion charge on chain aggregate smoke particles produced by an exploding wire and from a hydrocarbon flame were studied with a system consisting of an electrical particle counter (EPC) and classifier and a condensation nuclei counter (CNC) From measurements of particle electric mobility, electric charge, and numbers of primary particles per aggregate the fluid drag as a function of equivalent spherical diameter was measured and compared with three different theories.It was found that for aggregates consisting of from 10 to 300 primary particles having a mass mean diameter on the order of 0.05μ, the fluid drag was nearly the same as that of a sphere having a volume equivalent to that of the aggregate. The diffusion charge was found to be about 70% higher than that of the equivalent sphere.The theory and data suggest that the relative independence of fluid drag and shape for this size aggregate is due to the opposite effects of increased surface area and gaseous slip.

I.—Focusing of Electron Beams in Crossed Static Electric and Magnetic Fields

SynopsisIn a crossed static homogeneous electric and magnetic field charged particles describing trochoidal orbits in a plane perpendicular to the direction of the magnetic field are focused, but a beam emitted by a point source in a finite solid angle spreads out indefinitely in the direction parallel to the magnetic field. The essential characteristics of trochoidal orbits can be preserved if the superimposed magnetic and electric fields are two-dimensional and orthogonal, such as derived from a vector potential, say, Ax = A(y, z), Av = Az = O, and a scalar potential Ф(y, z)= const. A(y, z). The focusing properties of such a field combination depend on the distribution of the magnetic field only. Following some general considerations, specific examples of double focusing field distributions are given, and the electron motion in one of them is treated in detail.