A new mechanism of radiation emission in the polar gap of a pulsar is proposed. It is the curvature radiation emitted by positrons moving towards the surface of the neutron star along inclined magnetic field and refle...A new mechanism of radiation emission in the polar gap of a pulsar is proposed. It is the curvature radiation emitted by positrons moving towards the surface of the neutron star along inclined magnetic field and reflected from the surface. Such radiation interferes with transition radiation emitted from the neutron star when positrons hit the surface. Proposed mechanism explains the mystery of the interpulse shift in the Crab pulsar at high frequencies discovered by Moffett and Hankins twenty years ago. We have found also reflected energy flux and spectrum, discussed coherence and disappearance of interpulse shift with increase of frequency.展开更多
As semiconductor technologies have been shrinking,the speed of circuits,integration density,and the number of I/O interfaces have been significantly increasing.As a consequence,electromagnetic emanation(EME)becomes a ...As semiconductor technologies have been shrinking,the speed of circuits,integration density,and the number of I/O interfaces have been significantly increasing.As a consequence,electromagnetic emanation(EME)becomes a critical issue in digital system designs.Electronic devices must meet electromagnetic compatibility(EMC)requirements to ensure that they operate properly,and safely without interference.I/O buffers consume high currents when they operate.The bonding wires,and lead frames are long enough to play as efficient antennas to radiate electromagnetic interference(EMI).Therefore,I/O switching activities significantly contribute to the EMI.In this paper,we evaluate and analyze the impact of I/O switching activities on the EME.We will change the circuit configurations such as the supply voltage for I/O banks,their switching frequency,driving current,and slew rate.Additionally,a trade-off between the switching frequencies and the number of simultaneous switching outputs(SSOs)is also considered in terms of EME.Moreover,we evaluate the electromagnetic emissions that are associated with the different I/O switching patterns.The results show that the electromagnetic emissions associated I/O switching activities depend strongly on their operating parameters and configurations.All the circuit implementations and measurements are carried out on a Xilinx Spartan-3 FPGA.展开更多
文摘A new mechanism of radiation emission in the polar gap of a pulsar is proposed. It is the curvature radiation emitted by positrons moving towards the surface of the neutron star along inclined magnetic field and reflected from the surface. Such radiation interferes with transition radiation emitted from the neutron star when positrons hit the surface. Proposed mechanism explains the mystery of the interpulse shift in the Crab pulsar at high frequencies discovered by Moffett and Hankins twenty years ago. We have found also reflected energy flux and spectrum, discussed coherence and disappearance of interpulse shift with increase of frequency.
基金Project(2018R1D1A1B07043399)supported by Basic Science Research Program through the National Research Foundation,Korea
文摘As semiconductor technologies have been shrinking,the speed of circuits,integration density,and the number of I/O interfaces have been significantly increasing.As a consequence,electromagnetic emanation(EME)becomes a critical issue in digital system designs.Electronic devices must meet electromagnetic compatibility(EMC)requirements to ensure that they operate properly,and safely without interference.I/O buffers consume high currents when they operate.The bonding wires,and lead frames are long enough to play as efficient antennas to radiate electromagnetic interference(EMI).Therefore,I/O switching activities significantly contribute to the EMI.In this paper,we evaluate and analyze the impact of I/O switching activities on the EME.We will change the circuit configurations such as the supply voltage for I/O banks,their switching frequency,driving current,and slew rate.Additionally,a trade-off between the switching frequencies and the number of simultaneous switching outputs(SSOs)is also considered in terms of EME.Moreover,we evaluate the electromagnetic emissions that are associated with the different I/O switching patterns.The results show that the electromagnetic emissions associated I/O switching activities depend strongly on their operating parameters and configurations.All the circuit implementations and measurements are carried out on a Xilinx Spartan-3 FPGA.
