The network structure of GEO Multi-beam satellite communications network is analyzed. The model of integrated space-ground radio resource management in combination of centralized mode and distributed mode is proposed. For the quality of service(QoS) support and the special requirement of anti-jamming,some research suggestions on call admission control,beam handoff management and packet scheduling are given.
Abstract We explore the axionic dark matter search sensitivity with a narrow-band detection scheme aimed at the axion-photon conversion by a static electric field inside a cylindrical capacitor. An alternating magnetic field signal is induced by effective currents as the axion dark matter wind flows perpendicularly through the electric field. At low axion masses, such as in a KKLT scenario, front-end narrow band filtering is provided by using LC resonance with a high Q factor, which enhances the detectability of the tiny magnetic field signal and leads to thermal noise as the major background that can be reduced under cryogenic conditions. We demonstrate that high $$g_{a\gamma }$$ gaγ sensitivity can be achieved by using a strong electric field $$E\sim $$ E∼ MVm $$^{-1}$$ -1 . The QCD axion theoretical parameter space would require a high $$E\sim $$ E∼ GVm $$^{-1}$$ -1 field strength. Using the static electric field scheme essentially avoids exposing the sensitive superconducting pickup to an applied laboratory magnetic field.
Axions and axion-like particles (ALPs) are very attractive dark matter candidates. In this review, we briefly investigate how the cosmological observations reveal the existence of dark matter and some unique properties of axions/(ALPs) which make them more interesting.
The dark photon is a promising candidate for the dark matter which comprises most of the matter in our visible Universe. Via kinetic mixing with the Standard Model it can also be resonantly converted to photons in an electromagnetic cavity, offering novel experimental possibilities for the discovery and study of dark matter. We report the results of a pathfinder dark photon dark matter cavity search experiment performed at Hunan Normal University and the Institute of Physics, Chinese Academy of Sciences, representing the first stage of the Axion and dark Photon EXperiment program. Finding no statistically significant excess, we place an upper limit on the kinetic mixing parameter |χ|<3.7×10−13 around mA≃29.5μeV at 90% confidence level. This result exceeds other constraints on dark photon dark matter in this frequency range by roughly an order of magnitude. Published by the American Physical Society 2024
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