Showing papers on "Dipole model of the Earth's magnetic field published in 1987"
TL;DR: In this paper, Tsyganenko and Usmanov's model was further developed, using IMP -A, C, D, E, F, G, H, I, J and HEOS -1, -2 spacecraft measurements made during 1966-1980.
519 citations
TL;DR: In this paper, it was found that there is a strong correlation between the electron properties and the sector structure of the magnetic field, and that anomalous scattering increases significantly toward sector boundaries for all energies up to several hundred eV.
Abstract: Variations of electron distribution functions in the solar wind have been investigated using the electron data observed aboard Helios 2 during the first four months of its mission in 1976 in the distance range between 0.3 and 1 AU. In particular, variations across the sector structure of the interplanetary magnetic field and across the plasma stream structures have been studied. It has been found that there is a strong correlation between the electron properties and the sector structure of the magnetic field. Within the interior of magnetic sectors the electron distribution functions are extremely anisotropic and skewed with respect to the magnetic field direction at high particle energies. Toward sector boundaries the electron distribution functions become less anisotropic and less skewed. Right at sector boundaries the electrons are relatively cool, and their distributions are nearly isotropic often showing a slight bidirectional anisotropy. These observations have been interpreted to indicate that scattering of electrons with energies above 100 eV is weak within the interior of magnetic sectors but anomalous scattering increases drastically toward sector boundaries for all energies in the halo regime up to several hundred eV. There is evidence for closed magnetic field structures, probably occurring frequently in the solar wind, where the magnetic field lines should usually be connected to the sun outside sector boundaries but may or may not be disconnected from the sun at sector boundaries.
164 citations
TL;DR: Aspherical harmonic model of the magnetic field of Uranus was obtained from the Voyager 2 encounter observations using generalized inverse techniques which allow partial solutions to complex (underdetermined) problems as mentioned in this paper.
Abstract: Aspherical harmonic model of the planetary magnetic field of Uranus is obtained from the Voyager 2 encounter observations using generalized inverse techniques which allow partial solutions to complex (underdetermined) problems. The Goddard Space Flight Center 'Q3' model is characterized by a large dipole tilt (58.6 deg) relative to the rotation axis, a dipole moment of 0.228 G R(Uranus radii cubed) and an unusually large quadrupole moment. Characteristics of this complex model magnetic field are illustrated using contour maps of the field on the planet's surface and discussed in the context of possible dynamo generation in the relatively poorly conducting 'ice' mantle.
144 citations
TL;DR: In this paper, it was shown that the solar magnetic fields are intrinsically strong and that reconnection and merging of magnetic fields take place continually under the conditions presently examined, and that merging of IN fields is more important than the ephemeral regions as a source of new network elements.
Abstract: Videomagnetograph observations of the weak solar magnetic fields are discussed. Intranetwork (IN) elements are found to emerge in bipolar form, but to flow in a random pattern rather than toward the network elements. Merging of IN fields is found to be more important than the ephemeral regions as a source of new network elements. Arguments for and against the hypothesis that all solar fields are intrinsically strong are considered. It is noted that reconnection and merging of magnetic fields take place continually under the conditions presently examined.
72 citations
TL;DR: In this article, the behavior and time evolution of the large-scale magnetic fields and plasma of the dayside Venus ionosphere were studied using a one-dimensional model, where coupled continuity, momentum, and Maxwell's equations were solved simultaneously for O(+), O2+ and H(+) and the magnetic field.
Abstract: The behavior and time evolution of the large-scale magnetic fields and plasma of the dayside Venus ionosphere are studied using a one-dimensional model. The coupled continuity, momentum, and Maxwell's equations are solved simultaneously for O(+), O2(+), and H(+), and the magnetic field. The calculated magnetic field profiles are in good agreement with Pioneer Venus orbiter magnetometer observations. The magnetic field structure is quasi-steady for slow changes of the solar wind dynamic pressure. The peak at 165 km is maintained by downward convection from higher altitudes. The time scale for the decay of the field by the pure one-dimensional vertical diffusion/convection process is several hours unless the flux is resupplied from the top of the ionosphere.
53 citations
TL;DR: In this paper, the authors used quasi-linear theory applied to a slab model for the mean free path during the passage of the closed loop and inferred that the proton regime associated with the loop structure is experiencing scatter-free transport and that either the length of the loop is approximately 3 AU between the sun and the earth or else the protons are being reflected at both ends of a smaller loop.
Abstract: Correlated particle and magnetic field measurements by the ISEE 3 spacecraft are presented for the loop structure behind the interplanetary traveling shock event of Nov. 12, 1978. Following the passage of the turbulent shock region, strong bidirectional streaming of low-energy protons is observed for approximately 6 hours, corresponding to a loop thickness of about 0.07 AU. This region is also characterized by a low relative variance of the magnetic field, a depressed proton intensity, and a reduction in the magnetic power spectral density. Using quasi-linear theory applied to a slab model, a value of 3 AU is derived for the mean free path during the passage of the closed loop. It is inferred from this observation that the proton regime associated with the loop structure is experiencing scatter-free transport and that either the length of the loop is approximately 3 AU between the sun and the earth or else the protons are being reflected at both ends of a smaller loop.
43 citations
TL;DR: In this paper, high-resolution magnetic field and charged-particle data acquired on March 25, 1986 by the Viking and DMSP-F7 satellites, as they traversed the dawn sector auroral zone on nearly antiparallel trajectories within 40 min of each oher, are analyzed.
Abstract: High-resolution magnetic field and charged-particle data acquired on March 25, 1986 by the Viking and DMSP-F7 satellites, as they traversed the dawn sector auroral zone on nearly antiparallel trajectories within 40 min of each oher, are analyzed. Magnetic field measurements by Viking at 0850 MLT and by DMSP at 0630 MLT indicate the presence of a large-scale earthward-directed region 1 Birkeland current and an upward-flowing region 2 current. Both satellites also observed a third Birkeland current adjacent to and poleward of the region 1 system with opposite flow. This poleward system is about 0.5 deg invariant latitude wide and has a current density comparable to the region 1 and 2 systems. The highest-latitude current is identified as region 0. Its charged-particle signatures were used to infer field line mapping to the equatorial plane.
36 citations
TL;DR: An asymptotic solution of generation equations for the solar mean magnetic field is given and studied in this article, where the variation of rotational angular velocity with depth is taken from helioseismological data.
Abstract: An asymptotic solution of generation equations for the solar mean magnetic field is given and studied. The variation of rotational angular velocity with depth is taken from helioseismological data. Average helicity is prescribed according to the mixing length theory. It is shown that three dynamo waves of the magnetic field are excited. The first wave is generated at the surface layer and concentrates at latitudes of about 60°. Its activity becomes apparent in the poleward migration of the zone of polar faculae formation. The second more powerful wave of the field is excited in the center of the convection zone and its activity shows up in a sunspot cycle. The third wave which is similar to the first wave, is generated at the bottom of the convection zone and attenuates towards the surface. Its activity may appear as a three-fold reversal of the polar magnetic field.
26 citations
TL;DR: The evidence for the existence of the magnetic field of the planet Mars and for the effectiveness of the dipolar part of the field as an obstacle to the solar wind at the most frequent parameters of the latter is presented in this paper.
Abstract: The evidence is presented for the existence of the magnetic field of the planet Mars and for the effectiveness of the dipolar part of the field as an obstacle to the solar wind at the most frequent parameters of the latter. The dipolar magnetic moment of Mars is (1.5–2.20 × 1022 G cm3. The dipole axis makes an angle i⩽15‡ with the rotation axis of the panel. The magnetic north pole of Mars is located in its southern hemisphere. In terms of the precession dynamo model, the magnetic fields of the Earth and Mars are similar. This indicates that the Martian magnetic field is associated with the present-day dynamo-process in the Martian liquid core.
20 citations
TL;DR: In this article, an exact equation for the magnetic field lines of the general axisymmetric magnetic multipole of arbitrary degree (n) has been derived for the possible nature of solarterrestrial physics during geomagnetic polarity reversals.
Abstract: Summary. An exact equation is derived for the magnetic field lines of the general axisymmetric magnetic multipole of arbitrary degree (n). This new result has important applications in studies of the possible nature of solarterrestrial physics during geomagnetic polarity reversals. In the limiting case of a magnetic dipole (n = l), the equation for the magnetic field lines of the general axisymmetric magnetic multipole simplifies correctly to the wellknown dipolar form, which is used extensively in geomagnetism, magnetospheric physics and cosmic-ray physics as a first-order approximation to the actual configuration of the geomagnetic field. It is also shown theoretically that suites of similar magnetic field lines of the general axisymmetric multipole attain their maximum radial distances from the origin on a set of circular conical surfaces, with coincident vertices at the centre of the Earth; this set includes the equatorial plane if the degree (n) of the multipole is odd. The magnetic field is horizontal everywhere on all these surfaces. Palaeomagnetic studies have suggested that during some polarity reversals the magnetic field in the inner magnetosphere can be represented approximately either by a single, non-dipolar, low-degree (2 < n < 4), axisymmetric magnetic multipole or by a linear combination of such multipoles. In this situation, the equation for the field lines of an axisymmetric magnetic multipole of low degree (2 < n < 4) would be as fundamental to a proper understanding of magnetospheric, ionospheric and cosmic-ray physics during polarity reversals as is the equation for dipolar field lines in the case of the contemporary geomagnetic field.
18 citations
TL;DR: In this paper, changes of the neutral line on the source surface (analogous to the magnetic dip equator of the earth) during the period between 1976 and 1983 are examined on the basis of the Stanford solar magnetic field data.
Abstract: Changes of the neutral line on the source surface (analogous to the magnetic dip equator of the earth) during the period between 1976 and 1983 are examined on the basis of the Stanford solar magnetic field data. Instead of the standard Mercator-like projection, the neutral line is shown on a spherical surface for 16 selected Carrington rotations. In spite of great complexity of the field variations, this presentation depicts clearly a fairly systematic rotational reversal of the dipolar field on the source surface during the sunspot maximum years. It is suggested that this solar situation is somewhat analogous to the planet earth in the sense that the core surface and the earth's surface may correspond to the photosphere and the source surface, respectively.
TL;DR: In this paper, a strong correlation exists between large-scale downward-flowing Birkeland currents (region 1 system) and impulsive electrostatic waves in data acquired by the High Frequency Wave and Magnetic Field instruments on the Viking satellite.
Abstract: Impulsive electrostatic waves have been observed in regions of downward-flowing region 1 Birkeland currents in data acquired by the High Frequency Wave and Magnetic Field instruments on the Viking satellite. These data were obtained at approximately 11,000 km altitude and in the 1100 MLT and 76° invariant latitude sector near the equatorward boundary of the dayside polar cusp. Wave and magnetic field data are presented from Viking orbit 1219 on October 1, 1986, and wave, magnetic field, and particle data acquired with the Hot Plasma instrument from orbit 1197 on September 27, 1986. The high frequency waves are observed between the electron plasma and cyclotron frequencies. Since the broadband electrostatic waves extend in frequency above the cold plasma frequency, a nonlinear treatment must be made to explain the observation. We suggest that electron acoustic waves may couple with other electron plasma waves, resulting in the distribution of wave power over a wide range of frequencies. A strong correlation exists between large-scale downward-flowing Birkeland currents (region 1 system) and impulsive electrostatic waves. The Viking Magnetic Field experiment allows one to resolve, in high time-resolution, electron beams that may be unstable to the impulsive electrostatic waves.
TL;DR: Based on the ion plasma and magnetic field observations of Vega−1 near its closest approach to comet Halley, a selfconsistent scenario is developed according to which the observed magnetic field topology, the observed burst of ions at energies 200-600 eV, and the observed directional dependence of the flow of these ions leads to the conclusion that these burst-particles are cometary ions which have been accelerated by the process of merging of magnetic field lines of opposite polarity as discussed by the authors.
Abstract: Based on the ion plasma and magnetic field observations of Vega−1 near its closest approach to comet Halley a self-consistent scenario is developed according to which the observed magnetic field topology, the observed burst of ions at energies 200–600 eV, and the observed directional dependence of the flow of these ions leads to the conclusion that these burst-particles are cometary ions which have been accelerated by the process of merging of magnetic field lines of opposite polarity.
TL;DR: In this paper, the typical circular cellular-like features, which are striking during some intervals in the large scale distribution of weak magnetic fields measured with low resolution, are related to large-scale convective motions.
Abstract: We have tried to decide whether the typical circular cellular-like features, which are striking during some intervals in the large-scale distribution of weak magnetic fields measured with low resolution, are related to large-scale convective motions. Two scales of such patterns were found and their morphological, kinematical and evolutionary behaviour was estimated. Their slower and overall rotation is also demonstrated in comparison with the rotation of highly averaged sunspot and magnetic fields. It is difficult to explain all the observed characteristics as random, or due to the method of field measurement and map construction used. We also discuss the change of their magnetic field polarities with the solar polar field reversal.
TL;DR: In this article, the authors analyzed the entire flyby of Saturn's magnetic field by fitting a magnetospheric dipole field, higher moments of the internal field aligned with the dipole along the rotation axis, and the field due to an equatorial sheet current to the magnetic measurements.
Abstract: Pioneer 11 and Voyager 1 and 2 magnetic field measurements over the entire flyby of Saturn's magnetic field have been analyzed by fitting a magnetospheric dipole field (i.e., a dipole field plus the field due to currents in the magnetopause), higher moments of the internal field aligned with the dipole along the rotation axis, and the field due to an equatorial sheet current to the magnetic measurements. A dipole moment of 21,431 nT R(s) exp 3, a quadrupole moment of 2403 nT R(s) exp 4, an octopole moment of 2173 nT R(s) exp 5, and an equatorial sheet current of half thickness 2.0 R(s) from about 5 R(s) to the solar edge of the magnetopause, fit the measurements over the entire magnetosphere with an rms deviation of 3.2 nT where R(s) is the planet radius, 66,330 km. The primary feature of the present analysis is the explicit inclusion of the calculated magnetopause current field, which reduces the overall rms deviation over the entire flyby from sigma values of 4.7 and 5.9 nT, using previous models, to 3.2 nT using the present.
01 Aug 1987
TL;DR: In this paper, the nature of the nonlinear evolution of Kelvin-Helmholtz instability in the presence of sheared magnetic fields was investigated via numerical simulation models of the magnetosheath-magnetopause boundary in earth's tail and stream interaction regions in the inner heliosphere were studied.
Abstract: The nature of the nonlinear evolution of Kelvin-Helmholtz instability in the presence of sheared magnetic fields was investigated via numerical simulation Models of the magnetosheath-magnetopause boundary in earth's tail and stream interaction regions in the inner heliosphere were studied The development of the instability is influenced strongly by the orientation and magnitude of the magnetic field Large vortical structures that resemble observations in the earth's tail can form while other cases generate turbulent spectra that provide insight into the generation of Alfven turbulence in the solar wind
TL;DR: In this paper, an analytic magnetic field model for the Earth's magnetosphere is constructed from a dipole field and a tail field, which can be taken as a generalization of the Dungey's model, after one adds to it a horizontal component.
Abstract: An analytic magnetic field model for the Earth's magnetosphere is constructed from a dipole field and a tail field. This model can be taken as a generalization of the Dungey's model, after one adds to it a horizontal component. The magnetic topology in the noon-midnight meridian plane of this model is fully determined and it is compared with the topology of other models. In this study it is found that, for a specific value of the parameterk, which is associated to any form of the model, the noon's side neutral points obey a bifurcation scheme.
TL;DR: In this paper, the authors identify the configurations corresponding to extrema of the field energy, i.e., a point on an energy plane (the flat limiting case of a saddle) and not to a minimum.
Abstract: The dipole field represents a magnetic paradigm. It occurs in a hierarchy of scale, from elementary particles, to ferromagnetic domains, to laboratory magnets, up to the earth itself. Nevertheless, the present magnetic paradigm for plasma physics and astrophysics is not the dipole, but the Beltrami field , k a constant or scalar function. Such fields are regarded as the most stable, and are extensively used in models of cosmic and laboratory plasmas. The problem is that these two classes of supposedly paradigmatic vector fields are incompatible, as it is impossible to transform one into the other via a continuous limiting process. This paper attempts to resolve this basic contradiction by identifying the configurations corresponding to extrema of the field energy. It is found that, contrary to a long-held belief, Beltrami fields correspond to a point on an energy plane (the flat limiting case of a saddle) and not to a minimum. The classes of energy minima derived here include axisymmetric toroidal and axisymmetric poloidal fields. The latter naturally reduce to dipole fields in the limit of a microscopic current, in agreement with the magnetic paradigm. Some of the situations which have traditionally used Beltrami fields as a model can be explained with the minimum-energy fields derived here. The observed instability of axisymmetric magnetoplasmas follows from a separate energy equipartitioning mechanism.
01 Jan 1987
TL;DR: In this article, a preliminary investigation into the existence of large scale magnetic fields in the Sun is given, using a kinematic model with prescribed internal rotation and a standard solar model, the poloidal and toroidal components of the magnetic field are calculated.
Abstract: In this paper results of a preliminary investigation into the existence of large scale magnetic fields in the Sun are given. Using a kinematic model with prescribed internal rotation and a standard solar model, the poloidal and toroidal components of the magnetic field are calculated. The basic decay time is of the order of the age of the Sun. In addition the fields are quite sensitive to slight variations in the internal rotation. The boundary condition at the sofar suriace also does not seem to influence the inner regions where large scale fields seem possible.
TL;DR: In this article, the effect of thin conducting sheet on the fields of a subsurface vertical magnetic dipole has been analyzed numerically and numerical results for the vertical magnetic field above the source at the surface are presented in parametric form.
Abstract: The effect of a thin conducting sheet on the fields of a subsurface vertical magnetic dipole has been analyzed. The integral representation of the fields has been evaluated numerically, and numerical results for the vertical magnetic field above the source at the surface are presented in parametric form. It is found that the predicted fields give better agreement with previous transmission measurements than do the fields of a homogeneous half-space model.
TL;DR: In this article, radio signals from Uranus at 481.2 kHz were analyzed according to the magnetic latitude of the observer in an offset tilted dipole field model, and a sharply defined emission beam extending from 25 to 55 deg latitude was evident consistent with a source over the south magnetic pole.
Abstract: Radio waves from Uranus at 481.2 kHz detected by Voyager 2 show a strong beaming effect. When the data are analyzed according to the magnetic latitude of the observer in an offset tilted dipole field model, a sharply defined emission beam extending from 25 to 55 deg latitude is evident consistent with a source over the south magnetic pole. The lack of prominent emission from the north magnetic pole can be attributed to the large spatial offset of the magnetic dipole resulting in much lower source frequencies. For proper alignment of the beam, an advance of the dipole axis longitude by 23 deg from the standard model is required. This phase shift is interpreted as the result of higher order magnetic moments producing a skew of the field lines at low altitudes in the polar source region. This conclusion further substantiates models of the interior of Uranus which predict a complex intrinsic field with significant nondipolar contributions to the surface magnetic field.
Journal Article•
TL;DR: The MPTE/CCE magnetic field experiment has been used to obtain a quantitative evaluation of the frequency and extent of magnetic field distortion in the near-tail region at less than 88 earth radii.
Abstract: The MPTE/CCE magnetic field experiment has been used to obtain a quantitative evaluation of the frequency and extent of magnetic field distortion in the near-tail region at less than 88 earth radii The variation of this distortion with Kp, radial distance, longitude, and near-equatorial latitude is reported It has been found that taillike distortions from the dipole field direction may reach 80 deg near the MPTE/CE apogee of 88 earth radii The Bz field component in dipole coordinates was always positive within 05 earth radii of the equatorial current sheet, indicating the neutral lines were never seen inside of 88 earth radii Fields were most taillike near midnight and during times of high Kp At 85 earth radii the equatorial field magnitude depressions were roughly half the dipole field strength of 51 nT These depressions are larger at lesser distances, reaching -40 nT at 34 earth radii for Kp of 2- or less and -80 nT and Kp of 3+ and greater
30 Jun 1987
TL;DR: In this article, the authors present a fast scan program with Magnetic and Velocity Maps (MVMs) and Limb Shift, and Differential Rotation with Altitude (DRA).
Abstract: : Contents: Fast-Scan Program; Magnetic and Velocity Maps; Limb Shift; and Differential Rotation with Altitude.
01 Jan 1987
TL;DR: Anzer and Tandberg-Hanssen as discussed by the authors measured magnetic fields in quiescent prominences and found that the magnetic field cross the prominence at a small angle of the order of 15°.
Abstract: Measurements of magnetic fields in quiescent prominences have a long tradition. Rust (1967) and Harvey (1969) made extensive studies of strengths and distributions of fields in prominences. Since they used the longitudinal Zeeman effect they could only obtain the line of sight component of the magnetic field Bll. They found typical field strengths of about 20 Gauss in quiescent prominences. They did not say anything about the direction of the field with respect to the long axis of these prominences. Based on the large number of observational data Anzer and Tandberg-Hanssen (1971) took a statistical approach to find a general trend for this field orientation. They found that in general the field crosses the prominence at a small angle of the order of 15°.
14 Aug 1987
TL;DR: In this article, the geometrical enhancement of scintillations observed during alignment of the propagation with the local magnetic L-shell is shown to be the most consistent and conspicuous feature of the nighttime auroral oval.
Abstract: : The orbiting HiLat satellite launched in 1983 offered an opportunity for studying ionospheric scintillation parameters in relation to in-situ measurements of ionization density, drift velocity, field-aligned current, and particle precipitation during the sunspot minimum period. This report discusses results of a morphological study based on observations of scintillations and total electron content (TEC) at the auroral oval station at Tromso, Norway, during the period Dec 1983 - Oct 1985. The geometrical enhancement of scintillations observed during alignment of the propagation with the local magnetic L-shell is shown to be the most consistent and conspicuous feature of scintillations in the nighttime auroral oval. The dynamics of the spatial and temporal extent of this region are illustrated in the invariant latitude/ magnetic local time grid. Steepening of phase spectral slope in the geometrical enhancement region is indicative of the presence of L-shell aligned sheet-like irregularities at long scale lengths. The seasonal variation of TEC determined from the differential Doppler measurements of HiLat transmissions is discussed in relation to the in-situ density measurements at 830 km. The results are also used to illustrate the dependence of ionospheric structure parameters on short- term variability of solar activity during the sunspot minimum period. This study provides an insight into the nature of magnetospheric coupling with the ionosphere at high latitudes.
01 Jan 1987
TL;DR: In this paper, a simple nonlinear model allows both multiply periodic and chaotic behaviour in a star's magnetic field and demonstrates that both aperiodic magnetic cycles and the irregular modulation responsible for grand minima can be regarded as examples of deterministic chaos.
Abstract: Stellar magnetic fields exert torques which, alter the distribution of angular momentum in a star. In the radiative interior of the Sun these torques tend to enforce uniform rotation and the existence of a rapidly rotating core would imply a poloidal field of less than 10–2 G. In the convective envelope magnetic fields generated by dynamo action produce torques which lead to torsional oscillations. A simple nonlinear model allows both multiply periodic and chaotic behaviour. This system demonstrates that both aperiodic magnetic cycles and the irregular modulation responsible for grand minima can be regarded as examples of deterministic chaos. This picture is consistent with the 14C record but implies that the multiply periodic lamination of some Precambrian varves is not associated with the solar cycle.
TL;DR: The Eos cover of the October 21, 1986 issue of Eos had an attractive cover showing the Viking satellite in space near the earth, and the artist's rendition of the magnetic field lines of the earth as discussed by the authors.
Abstract: The October 21, 1986, issue of Eos had an attractive cover showing the Viking satellite in space near the earth. It also showed an artist's rendition of the magnetic field lines of the earth. Since the field lines were symmetric (see Figure 1 for a version of the cover), and the closed lines that were shown only extended out to about 2 RE from the earth's center, I would have expected the lines to be those of a dipole. However, a dipole field line pattern is characterized by “lobes” that are comparatively long and narrow in a direction perpendicular to the dipole axis, and the field lines on the Eos cover were too compressed along the equatorial dimension to meet that criterion. Something was wrong.
01 Aug 1987
TL;DR: In this article, a model to predict the coupling of external magnetic fields into a cylindrical object through an aperture shielded with a metal screen is presented, and the results from an experiment designed to test the model are presented.
Abstract: Introduction This paper presents the development of a model to predict the coupling of external magnetic fields into a cylindrical object through an aperture shielded with a metal screen. Also presented, are the results from an experiment designed to test the model. The coupling of these exterior fields through a single elliptical aperture is approximated by the radiation from an equivalent dipole into the object. The magnetic moments for this dipole are determined by the physical size of the aperture. The screen is then modeled as a linear superposition of many individual aper tures. The total field at an interior point is calculated by summing the components of the fields from each of these apertures. In order to test this model, an aluminum cylinder was constructed to be used as a test object. This cylinder was the meters long with a diameter of one meter. The ends of the cylinder were tapered to provide a constant impedance at the terminations. The entire object was mounted in a multiple wire coaxial return path to provide a nominal 50 Ohm imped ance. The center section of the cylinder cylinder contained an aperture that was 1.5 m long and that extended along a circumferential arc of 120 degrees. Covers for this aperture were constructed using different sizes of expanded metal mesh. An impulsive current generator was used to inject currents axially onto the cylinder. The peak currents levels were up to 30 kiloamps (kA). The resulting magnetic fields across the screened aperture were measured and compared with the simul taneous fields at interior points.
TL;DR: In this paper, the motion of a charged particle is studied within a magnetic field by means of the adiabatic theory, and a numerical integration of the equations of motion is given.
Abstract: The motion of a charged particle is studied within a magnetic field. This field consists of two separate fields; a dipole and a uniform magnetic field, parallel to dipole's magnetic moment. The present study is maintained by means of the adiabatic theory. We use a numerical integration of the equations of motion and give comparative results between the adiabatic theory and the numerical integration. The previous results are applied to the case of the Earth's open magnetosphere. Diagrams and tables support this application.