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Particulate matter possessing lunar escape velocity sufficient to enhance the cislunar meteroid flux was investigated. While the interplanetary flux was extensively studied, lunar ejecta created by the impact of this material on the lunar surface is only now being studied. Two recently reported flux models are employed to calculate the total mass impacting the lunar surface due to sporadic meteor flux. There is ample evidence to support the contention that the sporadic interplanetary meteoroid flux enhances the meteroid flux of cislunar space through the creation of micron and submicron lunar ejecta with lunar escape velocity.

Data from multiple ground stations and satellites were used to see how the plasmasphere in the dusk sector is modified during magnetic storms. There is clearly some type of erosion process, during which the plasmasphere is diminished in size, and it is believed that the excess plasma is peeled off and carried (convected) away toward the outer boundary of the magnetosphere (the magnetopause). However, very little is know about the physics of the erosion process, and about how the plasmasphere recovers during the quiet periods that follow such disturbances. Case studies from three multiday periods in 1982 produced a number of new findings which are summarized in this two page document.

THE TEMPORAL EVOLUTION IS PRESENTED OF ION-SOUND TURBULENCE IN THE EARTH'S MAGNETOSPHERE. THE ORIGIN OF THE TURBULENCE IS ASSOCIATED WITH CURRENTS AND ELECTRIC FIELDS ALONG GEOMAGNETIC FIELD LINES. THE ANOMALOUS DISSIPATION OF THE LONGITUDINAL CURRENTS CAUSED BY TURBULENCE IS THE SOURCE OF GRADUAL HEATING OF THE PLASMA. THE DAMPING OF SHORT-PERIOD OSCILLATIONS OF THE MAGNETIC FIELD, CORRESPONDING TO MHD-WAVES IN THE MAGNETOSPHERE, MAY SERVE AS A DIAGNOSTIC MEASURE OF THIS PHENOMENON. AS CALCULATIONS SHOW, THE DAMPING SHOULD DECREASE WITH AN INCREASE IN PLASMA TEMPERATURE, AND, CONSEQUENTLY, WITH TIME. THE DAMPING DECREMENT OF SHORT-PERIOD OSCILLATIONS OBSERVED ON THE BACKGROUND OF SUFFICIENTLY INTENSE BAYS IS ANALYZED, AND IT IS OBSERVED THAT THE DAMPING DOES TEND TO DECREASE WITH TIME.

We study global non-axisymmetric oscillation modes and instabilities in magnetosphere- disc systems, as expected in neutron star X-ray binaries and possibly also in accreting black hole systems. Our two-dimensional magnetosphere-disc model consists of a Keplerian disc in contact with an uniformly rotating magnetosphere with low plasma density. Two types of global overstable modes exist in such systems, the interface modes and the disc inertial-acoustic modes. We examine various physical effects and parameters that influence the properties of these oscillation modes, particularly their growth rates, including the magnetosphere field configuration, the velocity and density contrasts across the magnetosphere-disc interface, the rotation profile (with Newtonian or General Relativistic potential), the sound speed and magnetic field of the disc. The interface modes are driven unstable by Rayleigh-Taylor and Kelvin-Helmholtz in- stabilities, but can be stabilized by the toroidal field (through magnetic tension) and disc differential rotation (through finite vorticity). General relativity increases their growth rates by modifying the disc vorticity outside the magnetosphere boundary. The interface modes may also be affected by wave absorption associated with corotation resonance in the disc. In the presence of a magnetosphere, the inertial-acoustic modes are effectively trapped at the innermost region of the relativistic disc just outside the interface. They are driven unstable by wave absorption at the corotation resonance, but can be stabilized by modest disc magnetic fields. The overstable oscillation modes studied in this paper have characteristic properties that make them possible candidates for the quasi-periodic oscillations observed in X-ray binaries.

We consider the classical picture of three dimensional motion of charged particles in pulsar magnetosphere. We adopt a perturbative method to solve the equation of motion, and find the trajectory of particles as they move along the rotating dipolar magnetic field lines. Our aim is to study the influence of rotation on the pulsar radio emission by considering the constrained motion of particles along the open dipolar magnetic field lines. We find that the rotation induces a significant curvature into the particle trajectories. Our model predicts the intensity on leading side dominates over that of trailing side. We expect that if there is any curvature induced radio emission from the region close to the magnetic axis then it must be due to the rotation induced curvature. Our model predicts the radius--to--frequency mapping (RFM) in the core emissions.

Extensive studies were conducted concerning the indivdual mass, temporal and positional distribution of micron and submicron lunar ejecta existing in the Earth-Moon gravitational sphere of influence. Initial results show a direct correlation between the position of the Moon, relative to the Earth, and the percentage of lunar ejecta leaving the Moon and intercepting the magnetosphere of the Earth at the magnetopause surface. It is seen that the Lorentz Force dominates all other forces, thus suggesting that submicron dust particles might possibly be magnetically trapped in the well known radiation zones.

Experiment: An energetic electron belt has been created in a laboratory terrella for the first time. Measurements indicate the trapped- electron belt to be localized in radius and have a non-Maxwellian energy distribution ranging from 10 to 40 keV. Using multiple probes, we have clearly identified drift-resonant instabilities leading to rapid radial transport. Transport in a dipole appears to require multiple modes, and its bursty nature suggests a profile relaxation of the energetic electrons which self-stabilizes the drift-resonant instabilities. Theory, Substorms in the magnetosphere cause the generation of major electromagnetic disturbances and energetic particles. We examine the role of the collisionless tearing-instability as a possible mechanism for substorms. Global asymptotic magnetotail equilbria which are slowly varying in the Earth-Sun direction are constructed, including all three components of the magnetic field. Some of these equilibria are analyzed for stability with respect to collisionless electron tearing modes. It is found that the ion tearing instability, which has been widely invoked as a possible trigger for substorms, does not exist. The By field is demonstrated to have a destabilizing effect on electron tearing modes. Regimes in which collisionless tearing modes can grow are delineated.

Based on a spatiotemporal analysis of POLAR UVI images, we show that the auroral emission events that initiate equatorward of the isotropic boundary (IB) obtained from a time-dependent empirical model, have systematically steeper power-law slopes of energy, power, area and lifetime probability distributions compared to the events that initiate poleward of the IB. The low-latitude group of events contains a distinct subpopulation of substorm-scale disturbances violating the power-law behavior, while the high latitude group is described by nearly perfect power-law statistics over the entire range of scales studied. The results obtained indicate that the inner and outer portions of the plasma sheet are characterized by substantially different scaling regimes of bursty energy dissipation suggestive of different physics in these regions.

It is shown how satellite magnetometer data at a magnetopause penetration can be used to determine the vector normal to the magnetopause current layer and the magnetic field component along this normal. Results from 22 Explorer 12 boundary penetrations indicate normal field components of less than 5 gamma in two-thirds of the cases. Measured field variations within the current layer demonstrate the existence of two fundamentally different types of boundary structure, the rotational and the tangential discontinuity. The rotational discontinuity seems to occur predominantly during magnetic storms. Finally, the calculated normal vector is compared with the normal to the surface of the Mead-Beard magnetosphere model.

The Earth's inner magnetosphere, a vast volume in space spanning from 1.5 Re (Earth radii) to 10 Re, is a host to a variety of plasma populations (with energy from 1 eV to few MeV) and physical processes where most of which involve plasma and field coupling. As a gigantic particle accelerator, the inner magnetosphere includes three overlapping regions: the plasmasphere, the ring current, and the Van Allen radiation belt. The complex structures and dynamics of these regions are externally driven by solar activities and internally modulated by intricate interactions and coupling. As a major constituent of Space Weather, the inner magnetosphere is both scientifically intriguing and practically important to our society. In this presentation, I will discuss our recent results from the Comprehensive Ring Current Model, in the context of our current understanding of the inner magnetosphere in general and challenges ahead in making further progresses.

Plasma turbulence in circumterrestrial space due to geomagnetic field related to dynamics of magnetosphere and electroconductivity

The Final Proceedings for Dynamics of the Magnetosphere and its Coupling to the Ionosphere on Multiple Scales held during the period 8 February 1999 - 13 February 1999. This is an interdisdplinary conference. Topics include solar-terrestrial interactions, magnetospheric physics, and magnetosphere-ionosphere coupling. Presentations will mainly be from the four-satellite Interball system, including joint studies with the US and Japanese ISTP satellites.

The objective of this research was to obtain new understanding of the thermal plasma structure and dynamics of the plasmasphere bulge region of the magnetosphere, with special emphasis on the erosion process that results in a reduction in plasmasphere size and on the manner in which erosion leads to the presence of patches of dense plasma in the middle and outer afternoon-dusk magnetosphere. Case studies involving data from the DE 1, GEOS 2, and ISEE 1 satellites and from ground whistler stations Siple, Halley, and Kerguelen were used. A copy of the published paper entitled 'A case study of plasma structure in the dusk sector associated with enhanced magnetospheric convection,' is included.

Our research program (1) demonstrated the relationship between the spectrum and intensity of low-frequency fluctuations and the collisionless transport of energetic trapped particles, (2) verified the applicability of the guiding-center drift Hamiltonian as the foundation for numerical simulation of driven particle flows, (3) derived a unified analytical theory of the electron and ion tearing instability in the presence of all three components of the tail magnetic field in order to identify a trigger for substorms, and (4) investigated the effect of small but finite resistivity on the dynamics of current-sheet formation in the solar corona. All topics originally proposed for study have been addressed by our studies and published within archival journals. In addition, our research uncovered entirely new topics of investigation which are the subject of new and separately funded research activities.

The research was motivated to understand the generation and transport of energetic particles found in laboratory, astrophysical and space plasmas. In particular, we studied the collisionless acceleration and transport of electrons driven by solar variability and the nonlinear dynamics of strong interchange instabilities. We created an artificial radiation belt in the laboratory, allowing the creation and study of intense interchange instabilities. Our investigations combined laboratory experimentation, computer simulation, and plasma theory. Recent measurements confirmed our self-consistent model for the nonlinear evolution of the interchange instability of hot plasma confined by dipolar magnetic fields. Additionally, we have discovered a mechanism to reduce the intensity on interchange instabilities by the application of high-frequency electromagnetic waves. Building on the knowledge gained through this research, we are conducting new investigations using support from the DOE/NSF partnership in basic plasma science. This work aims to understand the nonlinear dynamics of strong interchange instabilities in rotating dipole-confined plasma and to observe, for the first time in a single experiment, interchange instabilities excited by magnetic curvature and driven plasma convection.

The objective of the research has been to develop models of plasma processes in the earth's magnetosphere and ionosphere to understand processes responsible for auroral and magnetic phenomena. One major accomplishment has been the tentative identification of the process for generation of the electric potentials that accelerate auroral electrons. Another major accomplishment is a numerical model of auroral precipitation. The simulation indicate that anomalous resistivity plays little role in electron acceleration processes. The auroral simulation model indicates that the auroral beam may excite upper hybrid electrostatic waves, which may stochastically accelerate a portion of the electron beam to many tens of keV.