Effect of Upstream ULF Waves on the Energetic Ion Diffusion at the Earthʼs Foreshock. I. Theory and Simulation

Field-aligned diffusion of energetic ions in the Earth’s foreshock is investigated by using the quasi-linear theory (QLT)and test particle simulation

Effect of Upstream ULF Waves on the Energetic Ion Diffusion at the Earth's Foreshock. II. Observations

This study reports observations of energetic ions upstream of the Earth’s quasi-parallel bow shock by Cluster at times when interspacecraft separation distances were larg

Results of the search for inspiraling compact star binaries from TAMA300's observation in 2000-2004

We analyze the data of TAMA300 detector to search for gravitational waves from inspiraling compact star binaries with masses of the component stars in the range 1-3Msolar. In this analysis, 2705 hours of data, taken during the years 2000-2004, are used for the event search. We combine the results of different observation runs, and obtained a single upper limit on the rate of the coalescence of compact binaries in our Galaxy of 20 per year at a 90% confidence level. In this upper limit, the effect of various systematic errors such like the uncertainty of the background estimation and the calibration of the detector's sensitivity are included.Comment: 8 pages, 4 Postscript figures, uses revtex4.sty The author list was correcte

Observation results by the TAMA300 detector on gravitational wave bursts from stellar-core collapses

We present data-analysis schemes and results of observations with the TAMA300 gravitational-wave detector, targeting burst signals from stellar-core collapse events. In analyses for burst gravitational waves, the detection and fake-reduction schemes are different from well-investigated ones for a chirp-wave analysis, because precise waveform templates are not available. We used an excess-power filter for the extraction of gravitational-wave candidates, and developed two methods for the reduction of fake events caused by non-stationary noises of the detector. These analysis schemes were applied to real data from the TAMA300 interferometric gravitational wave detector. As a result, fake events were reduced by a factor of about 1000 in the best cases. The resultant event candidates were interpreted from an astronomical viewpoint. We set an upper limit of 2.2x10^3 events/sec on the burst gravitational-wave event rate in our Galaxy with a confidence level of 90%. This work sets a milestone and prospects on the search for burst gravitational waves, by establishing an analysis scheme for the observation data from an interferometric gravitational wave detector

Japanese market for dimensional lumber : a gravity model approach

The research was done using both descriptive and statistical analyses to investigate the Japanese market for dimensional lumber and how this might affect the demand for wood products from British Columbia. The data was collected from various publications obtained in both Japan and Canada. The descriptive analysis was focused on Japan's domestic forest industry and the Japanese market as lumber importer. The ownership and tenure of Japanese forest land was examined with particular focus on the role of public versus private owners. The financial health of primary operators and owners was also pursued. The level of domestic log and lumber production, prices and uses of timber are identified. Then, the interaction between the Japanese domestic market and the international market for logs and lumber was examined such as activities of major existent importers and the role of trading companies. The statistical analysis of the demand for dimensional lumber was developed. A commodity specific gravity model was utilized to integrate factors both in the supply and demand sides assuming lumber was differentiated by countries of origin. The underlying theories of the gravity model was first examined for the appropriate specification of the empirical model. The variables were also specified based on the information from the descriptive analysis. One conclusion was that non-price variables which indicate power relations between importer and exporter, and among exporters have a significant role in lumber trade with Japan; the variables were production capacities, absorption powers and dummy variables for each of the exporters. In contrast, price variables such as export/import prices, exchange rate have only small impacts on the trade flows. Since Japan's needs for lumber are so diversified, consumers in Japan may choose lumber by their own purpose; prices might be the secondary factor. Finally, as the world's resource market is moving in the direction of sustainable development and resource exporting countries are tightening regulation of their resource export, Japan has been forced to adjust her trade practises.Land and Food Systems, Faculty ofGraduat

Effect of whistler waves on electron bounce motion in the Earth's magnetotail

[[abstract]]Whistler waves play an important role in the scattering of energetic electrons in the Earth's magnetosphere. Pitch-angle scattering of trapped electrons caused by the wave-particle interaction via such waves violates the invariant of periodic bounce motion of the electrons in the dipolar magnetic field.We study the effects of whistler waves on the electron bounce motion in the Earths magnetotail by performing test particle simulations. We use three models for the background magnetic field; a uniform field, a pure dipolar field, and a stretched dipole-like field. Oblique whistler waves, localized around the magnetic equator, are given as a superposition of sinusoidal waves obeying a cold plasma dispersion relation. We solve a relativistic equation of motion of electrons in the given electromagnetic fields. Electron bounce periods are evaluated as functions of the electron energy and the initial pitch-angle and are compared with the adiabatic theory. We demonstrate that the electrons sometimes switch their guiding field lines due to the wave scattering, and their mirror points and bounce periods vary in time. We will discuss these results referring to a THEMIS observation of the dipolarization event detected at ˜10 RE tailside near the magnetic equator.[[notice]]補正完

Landau resonance between electrons and lower-hybrid waves in the inner magnetosphere

[[abstract]]Lower-hybrid waves are frequently observed near the geomagnetic equator in the inner magnetosphere (i.e., equatorial noise). They are in the frequency range between the proton gyrofrequency and the LH frequency, and were found to propagate approximately perpendicular to the background magnetic field with almost linear polarization. We have focused on the capability of the LH waves to scatter electrons, and showed that the diffusions could occur via both cyclotron and Landau resonances. To have the cyclotron resonance to occur, the electron energies should be higher than 1.56 MeV. On the contrary, the Landau resonance occurs even for relatively lower energies from 1.4 keV. Here, the linear resonance condition is assumed under the observed LH wave parameters such as the propagation angle of 85 degree and the frequency of 130 Hz in a plasma environment with the Alfven velocity of 1150 km/s. In this presentation, we discuss the Landau resonance between electrons and LH waves, by performing test particle simulation. The LH waves are given as a superposition of sinusoidal waves with different frequencies propagating highly perpendicular to the background magnetic field. The given waves obey the cold plasma dispersion relation. We evaluate the pitch-angle diffusion coefficient of electrons with energies from a few eV to 1 MeV. We discuss changes in pitch-angle distributions related to the diffusion processes.[[notice]]補正完

Electron Energization during Dipolarization Events by Test Particle Simulations

[[abstract]]In this research, we have developed a test particle simulation code to examine the electron energization during multiple dipolarization events. The Tao-Chan-Brizard guiding center model was implemented to evaluate the trajectories of 0.1, 1, 10 keV electrons with different initial pitch angles and L-shells. The time-varying magnetic field model was evaluated by the Tsyganenko model TS05 with the corresponding inductive electric field. Dipolarization events are characterized by an enhancement in particle energy in the nighttime magnetosphere. The increase in the magnetic field and the corresponding induced electric field can energize and transport the particles earthward, which can explain the mechanism of the particle flux enhancement in the inner magnetosphere. Numerical results will be compared with THEMIS measurements.[[notice]]補正完