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    Quantum theory of transition radiation and transition pair creation
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    view Abstract Citations (25) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Penrose pair production as a power source of quasars and active galactic nuclei. Kafatos, M. ; Leiter, D. Abstract Penrose pair production in massive canonical Kerr black holes (those with a/M equal to 0.998) is proposed as a way to explain the nature of the vast fluctuating energy production associated with active galactic nuclei and quasars. It is assumed that a Kerr black hole with a mass of the order of 100 million solar masses lies at the center of an active nucleus and that an accretion disk is formed. Penrose pair production in the inner ergosphere of such a massive canonical Kerr black hole is analyzed. The results indicate that: (1) particle pairs are ejected within a 40 deg angle relative to the equator; (2) the particle energy is of the order of 1 GeV per pair; (3) the pressure of the electron-positron relativistic gas is proportional to the electron-positron number density; (4) pair production may occur in bursts; and (5) the overall lifetime of an active nucleus would depend on the time required to exhaust the disk of its matter content. A test of the theory is suggested which involves observation of the 0.5-MeV pair-annihilation gamma rays that would be generated by annihilating particle pairs. Publication: The Astrophysical Journal Pub Date: April 1979 DOI: 10.1086/156928 Bibcode: 1979ApJ...229...46K Keywords: Active Galactic Nuclei; Black Holes (Astronomy); Pair Production; Quasars; Astronomical Models; Canonical Forms; Luminous Intensity; Space-Time Functions; Astrophysics; Black Holes; Black Holes:Galactic Nuclei; Black Holes:Quasars; Black Holes:Radio Galaxies; Black Holes:Seyfert Galaxies full text sources ADS |
    Pair production
    Black hole (networking)
    Annihilation
    Citations (15)
    High-frequency electromagnetic dynamics of charged or neutral atom beams which are widely used at present is analyzed. One of perspective mechanisms of radiation bound with high-frequency intratomic electronic transitions is considered. As it is shown a flux of fast nonexcited atoms, due to anomalous Doppler's transitions on slow waves in a gas or plasma, can be unstable and be a source of stimulated high-frequency radiation. As a whole process has a complex nature since photon radiation is accompanied by excitation of atoms with following emission of more high-frequency photons. The possible parameters of such physical systems are estimated.
    Transition radiation
    Energetic neutral atom
    Citations (0)
    We consider two-centre dielectronic transitions occurring in collisions of fast highly charged hydrogen-like projectiles with neutral atomic targets. In such collisions, in addition to the reaction channel due to the two-centre electron–electron interaction, the reaction channel induced by the two-centre electron–nucleus interactions becomes important. We show that the account of distortions of initial and final states of the target caused by the field of the projectile nucleus (which can also be viewed as imposing the Coulomb boundary conditions on these states) leads to an approach in which both these reaction channels are combined in a natural and relatively simple way. As a result, this approach enables one to extend calculations of different cross sections for two-centre dielectronic transitions from the high-velocity to the intermediate-to-high collision velocity regime.
    Electron capture
    Highly charged ion
    Figure 4. Contributions of `swaps' to the total charge exchange cross section (a) for kmin initial target states, (b) one swap, (c) three swaps, (d) five swaps and (e) seven swaps.
    Rydberg atom
    Charge exchange
    Electron capture
    To search for the lowest energy nuclear isomeric transition in 229Th in solid samples, a novel adsorption technique which prepares 229Th atoms on a surface of CaF2 is developed. Adsorbed 229Th is exposed to highly intensive undulator radiation in the wavelength range between 130 and 320 nm, which includes the indirectly measured nuclear resonance wavelength 160(10) nm. After the excitation, fluorescence from the sample is detected with a VUV sensitive photomultiplier tube. No clear signal relating to the nuclear transition is observed and possible reasons are discussed.
    Undulator
    Experimental results for the integral cross sections for the emission of Na(3p to 3s) and Na(4p to 3s) light after H+Na collisions at energies from 15 to 1500 eV are reported. The data are compared with model predictions.
    Low energy
    Citations (38)