摘要:

In a magnetoplasma, the amplitude of the lower oblique resonance in the mutual impedance of two electric antennas is very sensitive to the plasma frequency. This property can be used to measure the electron density in a simple way when the electron temperature and the magnetic field are known, provided also that the probe has been properly calibrated. As an application, densities are deduced from measurements made by a mutual‐impedance probe on a rocket in the auroral ionosphere. In the future, better practical design and theoretical modeling of the probe should make calibration unnecessary.

ISSN:0031-9171    

DOI:10.1063/1.864614

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Spectral measurements of the 3/2 harmonic emissions from 1.06 &mgr;m irradiated disk targets, and the 1/2 harmonic emissions from 0.53 &mgr;m irradiations, are presented. The splitting of the double‐peaked spectra show a distinct targetZdependence, for constant laser irradiation parameters. Possible generation mechanisms in terms of the two‐plasmon decay instability are discussed.

ISSN:0031-9171    

DOI:10.1063/1.864615

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Transport and implosion experiments have been conducted on the OMEGA 24‐beam, uniform‐irradiation facility. Thermal transport in spherical irradiation was found to be different than in comparable, single‐beam target irradiation and could not be described in terms of a flux‐inhibited model. Deep energy deposition in spherical irradiation (by electrons on the tail of the thermal velocity distribution) was found to lead to a temperature profile which is not as steep as predicted by a flux‐inhibited model. This apparently leads to more explosive implosion (i.e., higher core temperature) than predicted by using such a model.

ISSN:0031-9171    

DOI:10.1063/1.864616

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Counterstreaming large‐diameter electron beams in a steady‐state laboratory experiment are observed to generate transverse radiation at twice the upper‐hybrid frequency (2&ohgr;UH) with a quadrupole radiation pattern. The electromagnetic wave power density is nonlinearly enhanced over the power density obtained from a single beam–plasma system. Electromagnetic power density scales exponentially with beam energy and increases with ion mass. Weak turbulence theory can predict similar (but weaker) beam energy scaling but not the high power density, or the predominance of the 2&ohgr;UHradiation peak over the &ohgr;UHpeak. Significant noise near the upper‐hybrid and ion plasma frequencies is also measured, with normalized electrostatic wave energy densityWES/neTe≊10−2.

ISSN:0031-9171    

DOI:10.1063/1.864617

出版商:AIP    

年代:1984

数据来源: AIP

ISSN:0031-9171    

DOI:10.1063/1.864911

出版商:AIP    

年代:1984

数据来源: AIP