18,895 research outputs found
Effects of argon ion injections in the plasmasphere
In lifting massive space power system payloads from low Earth orbit to geosynchronous Earth orbit, Cargo Orbit Transfer (COTV) using ion propulsion will inject energetic beams of argon ions into the plasmasphere. The relationship of the beam velocity to Alfven and thermal velocities as a function of radial distance in the plasmasphere is given for positions near the Earth's equatorial plane. A beam sheath loss model is used which results in a deposition of argon ions and hence energy in the plasmasphere which is much less than that in models calling for clouds or plasma instabilities to rapidly stop the beam. A comparison is given of the cumulative fractional mass loss of an ion beam injected at 1.5 R for the ion cloud and the ion beam sheath loss process. The integrated difference of these two deposition models is shown for the construction of one SPS
Galactic cosmic ray heavy primary secondary doses
Results of a calculation which estimates the heavy primary secondary doses from cosmic ray interaction data are reported. The incident galactic cosmic ray heavy primary spectrum is represented as the sum of helium, nitrogen, magnesium, and iron components. The incident iron nuclei are allowed to fragment into lesser Z secondaries, which are assumed to travel in the same direction and start with the same energy per nucleon as the interacting primary. The total emergent particle energy spectra and dose are then presented for the galactic heavy primary spectrum incident on aluminum and tissue slabs. The importance of the fragmentation parameters assumed is also evaluated. The total dose from the heavy primaries and their secondaries is found to be reduced by only a factor of two in 20 g/sq cm of shielding
A study of radiation environment in space and its biological effects
Biological effects on man in space resulting from galactic and solar cosmic radiation are discussed. Importance of secondary ions which contribute to galactic cosmic radiation hazards is analyzed. Mathematical model to show rate of production of secondary ions of given atomic number at various points in absorber is presented
Changes in the terrestrial atmosphere-ionosphere-magnetosphere system due to ion propulsion for solar power satellite placement
Preliminary estimates of the effects massive Ar(+) injections on the ionosphere-plasmasphere system with specific emphasis on potential communications disruptions are given. The effects stem from direct Ar(+) precipitation into the atmosphere and from Ar(+) beam induced precipitation of MeV radiation belt protons. These injections result from the construction of Solar Power Satellites using earth-based materials in which sections of a satellite must be lifted from low earth to geosynchronous orbit by means of ion propulsion based on the relatively abundant terrestrial atmospheric component, Ar. The total amount of Ar(+) injected in transporting the components for each Solar Power Satellite is comparable to the total ion content of the ionosphere-plasmasphere system while the total energy injected is larger than that of this system. It is suggested that such effects may be largely eliminated by using lunar-based rather than earth-based satellite construction materials
Study of radiation hazards to man on extended missions
Radiation hazards on extended manned space flight
Higgs Boson in the 4DCHM: LHC phenomenology
Composite Higgs models provide an elegant solution to the hierarchy problem
present in the Standard Model (SM) and give an alternative pattern leading to
the mechanism of Electro-Weak Symmetry Breaking (EWSB). We present an analysis
of the Higgs boson production and decay within a recently proposed realistic
realization of this general idea: the 4D Composite Higgs Model (4DCHM).
Comparing our results with the latest Large Hadron Collider (LHC) data we show
that the 4DCHM could provide an alternative explanation with respect to the SM
of the LHC results pointing to the discovery of a Higgs-like particle at 125
GeV.Comment: Conference proceeding, EPS-HEP 2013, 18-24 July 2013, Stockholm. 3
pages, 2 figures, typo correcte
Production of Z' and W' via Drell-Yan processes in the 4D Composite Higgs Model at the LHC
We present an analysis of both the Neutral Current (NC) and Charged Current
(CC) Drell-Yan processes at the LHC within a 4 Dimensional realization of a
Composite Higgs model studying the cross sections and taking into account the
possible impact of the extra fermions present in the spectrum.Comment: Conference proceeding, XII IFAE Edition, 3-5 April 2013, Cagliari. 2
pages, 2 figures; v2 typo correcte
Study of radiation hazards to man on extended near earth missions
Radiation hazards to man on extended near earth mission
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