Particle beam weapons—a technical assessment

Bekefi, G.; Feld, Bernard T.; Parmentola, John; Tsipis, Kosta

doi:10.1038/284219a0

Cited by 21 publications

(6 citation statements)

References 16 publications

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“…This contrasts with the situation in most laboratory or terrestrial beams (e.g. , Bekefi et al , 1980). When large-scale magnetic stresses become dynamically important, MHD rather than gas dynamics is the relevant theoretical tool (see Sec.…”

Section: Il Physics Of Jetsmentioning

confidence: 85%

“…A different type of experiment which could achieve higher Mach numbers than "traditional" wind tunnels would involve the propagation of intense particle beams or, alternatively, laser beams -into the atmosphere (see Bekefi et al , 1980). Although the internal dynamics of such beams differ crucially from those in the cosmic-scale beams, they would provide a much higher momentum density than an ordinary gas jet.…”

Section: Experimental Prospectsmentioning

confidence: 98%

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Theory of extragalactic radio sources

1984

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Powerful extragalactic radio sources comprise two extended regions containing magnetic field and synchrotron-emitting relativistic electrons, each linked by a jet to a central compact radio source located in the nucleus of the associated galaxy. These jets are collimated streams of plasma that emerge from the nucleus in opposite directions, along which flow mass, momentum, energy, and magnetic flux. Methods of using the observations diagnostically to infer the pressures, densities, and fluid velocities within jets are explained. The jets terminate in the extended radio components, where they interact strongly with the surrounding medium through a combination of shock waves and instabilities. Jets may expand freely, be confined by external gas pressure, or be pinched by toroidal magnetic fields. Shear flows are known to be Kelvin-Helmholtz unstable and thus may be responsible for some of the observed oscillation of jets about their mean directions and for creating the turbulence and shock waves needed to accelerate the relativistic electrons. Larger-scale bending may be caused by changes in the jet axis within the nucleus, gravitational interaction of the radio galaxy with a companion galaxy, or rapid motion of the source through dense intergalactic gas. The compact radio sources also exhibit a jet morphology and contain more direct clues as to the origins of jets; in particular, the variations sometimes observed imply bulk flows that are relativistic. It is widely believed that nuclear activity is ultimately ascribable to gas accreting onto a massive black hole. The accretion can proceed in several different fashions, depending upon whether or not the gas has angular momentum and whether or not the radiation emitted is sufficiently intense to influence the dynamics of the flow. Several distinct mechanisms for jet production in the context of black holes have been proposed. (Alternative mechanisms involving dense star clusters and massive spinning stars are also reviewed. ) Supersonic jets may be collimated along the spin axis of a gas cloud surrounding the source of the lighter jet gas. Magnetic fields may be crucial in collimating jets, especially if they are wrapped around the jet by orbiting gas and can thereby collimate the outflow through the pinch effect. In fact, the spin energy of the black hole could also be extracted by magnetic torques, in which case the jet would contain electrons and positrons and carry a large electromagnetic Poynting flux. Statistical investigations of active galaxies also furnish valuable information on their nature and evolutionary behavior. The formation of particular kinds of sources appears to be correlated with environmental effects and cosmic epoch. In addition, the brightest compact radio sources on the sky, which probably involve relativistic motion, may be intrinsically faint objects beamed in our direction. There is now compelling evidence for the continuous fueling of extragalactic radio sources through jets emerging from the nucleus of the associated galaxy. The morpho...

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Section: Il Physics Of Jetsmentioning

confidence: 85%

Section: Experimental Prospectsmentioning

confidence: 98%

Theory of extragalactic radio sources

1984

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“…The interest in relativistic electron beam (REB) spreading in dense and rarefied gas plasma media has been greatly interest over the past decades by novel concepts in laboratory and plasma sciences [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. It is well known that the Ohmic and ionic plasma channel plays a central role in the transport of relativistic electron beam through gas plasma [15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Analytical treatment of the force acting on a relativistic electron beam spreading in dense gas plasma by the ohmic plasma channel

Мамедов

2015

Astroparticle Physics

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“…To reduce the importance of the latter phenomenon, the transport in a reduced-density channel has been proposed and experimented for years (Bekefi et al 1980). To reduce the importance of the latter phenomenon, the transport in a reduced-density channel has been proposed and experimented for years (Bekefi et al 1980).…”

Section: Introductionmentioning

confidence: 99%

Nonlinear electron beam guiding by a reduced-density channel

Dolique

Khodja

1993

Laser Part. Beams

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Suggested by numerical simulations, recent experiments have shown that a significant guiding force is exerted by a reduced-density channel on electron beams propagating through initially un-ionized air. A theoretical analysis of this guiding force had been given that assumed uniform beam and channel and small beam-channel offset. From a 2-D model, relative to a beam slice, the guiding force is calculated in this article for arbitrary beamchannel offset and for various smooth beam and channel profiles. This calculation confirms the above-quoted experimental evidence of a guiding force significant with respect to the deflection force exerted by the earth's magnetic field. It also confirms the crucial role played by the secondary electron temperature distribution. Finally, it suggests optimal values for the ratio between channel and beam rms radii.

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Particle beam weapons—a technical assessment

Cited by 21 publications

References 16 publications

Theory of extragalactic radio sources

Theory of extragalactic radio sources

Analytical treatment of the force acting on a relativistic electron beam spreading in dense gas plasma by the ohmic plasma channel

Nonlinear electron beam guiding by a reduced-density channel

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