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Existence of both subsonic and supersonic compressive solitons of interesting characters is established in this magnetized plasma model with non relativistic ions and relativistic electrons. The small supersonic range for the generation of compressive solitons is shown to confine near the vicinity of the direction of the magnetic field. It is predicted that the relativistic variation of electron’s mass is responsible for the expansion of Sagdeev potential to result increase in soliton’s amplitude and decrease in its width. 相似文献
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Compressive solitons of low and high amplitudes are established in this weakly relativistic and magnetized plasma model. The assigned direction of soliton propagation to the direction of the magnetic field, supplemented by the corresponding ion initial streaming speed (v iξ0) determines the lower limit of the initial electron streaming speed (v eξ0) in its interval of existence to produce solitons for a given value of the speed of light c. Further, lower limit of c specified by the corresponding energy (or temperature) to yield relativistic compressive solitons is also predicated. Interestingly, the increased initial streaming speed of electrons is found to play less effective role in the steepening growth of amplitudes of compressive solitons due to mode one than those corresponding to the mode two. 相似文献
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Yuichi Namegaya Yuichiro Tanioka Kuniaki Abe Kenji Satake Kenji Hirata Masami Okada Aditya R. Gusman 《Pure and Applied Geophysics》2009,166(1-2):97-116
Linear and nonlinear responses of ten well-type tide gauge stations on the Japan Sea coast of central Japan were estimated by in situ measurements. We poured water into the well or drained water from the well by using a pump to make an artificial water level difference between the outer sea and the well, then measured the recovery of water level in the well. At three tide gauge stations, Awashima, Iwafune, and Himekawa, the sea-level change of the outer sea is transmitted to the tide well instantaneously. However, at seven tide gauge stations, Nezugaseki, Ryotsu, Ogi, Teradomari, Banjin, Kujiranami, and Naoetsu, the sea-level change of the outer sea is not always transmitted to the tide well instantaneously. At these stations, the recorded tsunami waveforms are not assured to follow the actual tsunami waveforms. Tsunami waveforms from the Niigataken Chuetsu-oki Earthquake in 2007 recorded at these stations were corrected by using the measured tide gauge responses. The corrected amplitudes of the first and second waves were larger than the uncorrected ones, and the corrected peaks are a few minutes earlier than the uncorrected ones at Banjin, Kujiranami, and Ogi. At Banjin, the correction was significant; the corrected amplitudes of the first and second upward motion are +103 cm and +114 cm, respectively, while the uncorrected amplitudes were +96 cm and +88 cm. At other tide gauge stations, the differences between the uncorrected and corrected tsunami waveforms were insignificant. 相似文献
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Nguyen Dinh Chau Paweł Jodłowski Stefan J. Kalita Paweł Olko Edward Chruściel Adam Maksymowicz Michał Waligórski Paweł Bilski Maciej Budzanowski 《Acta Geophysica》2008,56(2):505-517
The doses of gamma radiation, concentrations of radium isotopes in water and sediments, radon concentration and concentration
of alpha potential energy of radon decay products in the copper ore mine and in the mining region in the vicinity of Lubin
town in Poland are presented. These data served as a basis for the assessment of radiological hazard to the mine workers and
general public. The results of this assessment indicate that radiological hazard in the region does not differ substantially
from typical values associated with natural radiation background. The calculated average annual effective dose for copper
miners is 1.48 mSv. In general, copper ore mines can be regarded as radiologically safe workplaces. 相似文献
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A finite difference implicit scheme is presented in this paper for solution of the shallow water equations in one dimensional (1D) form. The present model has many advantages like, handling of discontinuous and complex bed topography, satisfying C-property (preservation of motionless water surface over a wet or dry bed) and capability of handling large value of temporal step etc. Another very important feature of the present model is that, no special treatment of the source vector of the governing equations is required here to deal with very less water depth. To investigate the performance of the present model in diverse situations, it is used to replicate four different problems of known analytical solution, and the model is found to be quite capable for varied situations. 相似文献
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Amidst growing concern about the decline of the commons, this case underscores the importance of understanding how the commons are refashioned and remade to address emerging challenges in periurban spaces. This article describes how institutions surrounding the use of common property resources get transformed and evolve in periurban contexts. What were once johads – common property village ponds – undergo a change in their usage from storing rainwater to storing waste water of the city for irrigation. This emerges as a collective response to the uncertainty attached to the availability of waste water. New institutions evolve with regard to contributions to waste water infrastructure, as well as the appropriation of waste water. Further research should document the changing use of village commons and the emergence of new institutions governing them. 相似文献
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This study presents the future seismic hazard map of Coimbatore city, India, by considering rupture phenomenon. Seismotectonic
map for Coimbatore has been generated using past earthquakes and seismic sources within 300 km radius around the city. The
region experienced a largest earthquake of moment magnitude 6.3 in 1900. Available earthquakes are divided into two categories:
one includes events having moment magnitude of 5.0 and above, i.e., damaging earthquakes in the region and the other includes
the remaining, i.e., minor earthquakes. Subsurface rupture character of the region has been established by considering the
damaging earthquakes and total length of seismic source. Magnitudes of each source are estimated by assuming the subsurface
rupture length in terms of percentage of total length of sources and matched with reported earthquake. Estimated magnitudes
match well with the reported earthquakes for a RLD of 5.2% of the total length of source. Zone of influence circles is also
marked in the seismotectonic map by considering subsurface rupture length of fault associated with these earthquakes. As earthquakes
relive strain energy that builds up on faults, it is assumed that all the earthquakes close to damaging earthquake have released
the entire strain energy and it would take some time for the rebuilding of strain energy to cause a similar earthquake in
the same location/fault. Area free from influence circles has potential for future earthquake, if there is seismogenic source
and minor earthquake in the last 20 years. Based on this rupture phenomenon, eight probable locations have been identified
and these locations might have the potential for the future earthquakes. Characteristic earthquake moment magnitude (M
w
) of 6.4 is estimated for the seismic study area considering seismic sources close to probable zones and 15% increased regional
rupture character. The city is divided into several grid points at spacing of 0.01° and the peak ground acceleration (PGA)
due to each probable earthquake is calculated at every grid point in city by using the regional attenuation model. The maximum
of all these eight PGAs is taken for each grid point and the final PGA map is arrived. This map is compared to the PGA map
developed based on the conventional deterministic seismic hazard analysis (DSHA) approach. The probable future rupture earthquakes
gave less PGA than that of DSHA approach. The occurrence of any earthquake may be expected in near future in these eight zones,
as these eight places have been experiencing minor earthquakes and are located in well-defined seismogenic sources. 相似文献
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Our interest is to study the sheath formation in an inhomogeneous plasma coexisting with an interaction of weak ionization. Pseudopotential analysis has been employed to derive the coherent structures of sheath in plasma. It has shown that the ionization affects the growth of sheath in plasma and nature depends fully on plasma constituents as well. After getting a robust sheath, dynamical behaviors of a levitated dust grain into the robust sheath has been studied which, in fact, leads to find the variation of dust potential, dust sizes along with the net force generated on grains. Results are obtained numerical for some typical plasma parameters. It has demonstrated that the plasma constituent effects the clustering of dust grains in different region within the sheath as a result of which dust agglomeration forms nebulons: patches of dust cloud-like structures with changing fleece. 相似文献