Wang De-yu

A COLLECTIVE RADIATION MECHANISM FOR THE CORE EMISSION OF PULSARS

In the magnetic axial ambience of the rapidly rotating pulsar, the position beam has been accelerated by the gap of the intense electric field, and ejected with rotation around the magnetic axis. While there exists rare plasma envelope near the pulsar, such energetic and rotational positron beam may have those waves near the ion-cyclotron frequencies amplified in the direction of the magnetic field, by exciting Čerenkov and maser instabilities. These are a kind of coherence radiation which has a larger portion of circular polarization. Under this mechanism, the emerging of another radiation process from the pulsars, that is, the core emission can be satisfactorily explained. This paper also discusses some possible observations resulting from the mechanism.

A model of the galactic centre with magnetic monopoles

A model of the galactic centre with magnetic monopole has been presented here. The positron can be produced continuously through magnetic monopoles to induce baryon decay (Rubakov catalytic reaction) and a lot of energy can be released as well. The calculation results show that even if the galactic centre contains only a few magnetic monopoles (ζ = N M /N B ≈ 10 − 24), this massive object can not collapse into a black hole. This model can explain the observed intensities of the annihilation line and higher energy photons of E γ >511 keV from the galactic centre.

A model of the gamma-ray burst event of 1979 March 5 (paper I)

Abstract We discuss the time profiles and the energy spectra of the γ-ray burst event of 1979 March 5. We find: (1) the energy spectrum in the burst phase (

The spectrum of accelerated electrons induced by the ion cyclotron instability in coronal loops: AApS 13/2 (1993) 166–173

Assuming that the fast ions inject continually into coronal loop, the evolution of the fast ion stream introduced by the ion cyclotron ins ability in coronal loop and the process of the electron acceleration can be studied separately. In this paper, the quantitative expressions for the spectrum and flux of the accelerated electrons induced by the ion cyclotron instability are given in detail. Finally, some characteristics of the acceleration process and their possible applications are discussed.

Solar narrowband decimetric spike bursts and associated phenomena

Abstract Based on the observational data of solar narrowband decimetric spike bursts on 1981 Nov 12–14 (Enome et al. 1985) and, associated phenomena, we propose a model of two acceleration regions during the impulsive phase of solar flare. One (region A) is formed in the current sheet by magnetic reconnection process, the other (region B), at the top of the flaring loop by turbulence acceleration. Region B is able to generate mildly relativistic electrons and to emit gyrosynchrotron radiation or decimeter waveband microwave bursts. Two accelerated electron streams escape from region A simultaneously. One travels through the outer corona and excites type III bursts, the other, injected into the emerging flaring-loop at a certain pitch angle, will stimulate electron-cyclotron maser with a “hollow beam” distribution and emit narrowband decimetric spike bursts. Utilizing the formulae of “hollon beam” electron cyclotron maser, we have evaluated the maximum growth rate of the 2nd harmonic wave of FX mode and reached the following conclusions. As the energy of the downward electron stream increases, the maximum growth rate, probability of spike emissions, relative bandwidth and brightlness temperature all increase, the linear size of the spike source decreases, and the peak flux remains fixed. In addition, we have clarified the close association between narrow band spike bursts and type III bursts, and hard X-ray bursts.

A non-black hole model of galactic nuclei with monopoles

Abstract We use the magnetic monopole catalytic reaction of nuclear decay (the Rubakov-Callan effect) as energy source to build a non-black hole model of giant dense galactic nuclei containing monopoles below the Parker limit of ξ = N m / N B ≲ (−20 ± 1). Our conclusion is that, whenever the catalytic reaction exists, even if the cross section is less than (−26) cm 2 , it can produce enough energy to support supergiant nuclei, and avoid the black hole disaster. The main observational evidence for the present model is: the catalytic reaction will produce a copious stream of positrons, and the resulting strong pair annihilation line has been observed in the centre of our and other galaxies.

CONTENT OF MAGNETIC MONOPOLES IN QUASARS, GALACTIC NUCLEI AND STARS AND THEIR ASTROPHYSICAL EFFECTS

Estimations of the number of monopoles preserved and captured in the formation process of quasars, galactic nuclei and stars have been presented here. (ⅰ) The monopoles in quasars and other galactic nuclei are preserved in their formation process. And monopole content, ξ≡N m /N B , may be higher than the Newton saturation value, i. e. ξ≥ξN((?)2×10 25 ). (ⅱ) The monopoles in normal stars (including the sun), planets (e. g. the earth) and compact stars (white dwarfs and neutron stars) are mainly captive. For normal stars and planets ξ《ξN; for white dwarfs and neutron stars either ξ《ξN if the cross section of the Rubakov-Callan effect is much larger than 10 -2 , /10 -27 》10 -2 , or ξ﹋∽～ξN if not. (ⅲ) The monopoles in the center of the objects produce a radially magnetic field. The detection of the field may give limitations to the cross section of the RC effect.

A model of the γ-ray burst of 1979 March 5 (paper II)

Abstract We consider that the cosmic γ-ray burst of 1979 March 5 may have originated in a binary system containing a neutron star. If the stellar wind from the companion star is suddenly increased for some reason, a great quantity of plasma will pile up at the magnetopause of the neutron star, forming a high density accreting ring. When the mass of the plasma exceeds a critical value, the Krukal-Schwarzschild instability will set in and the plasma will pour into the magnetosphere. When the plasma reaches the surface of the star at the magnetic poles γ-ray and hard x-ray bursts will occur. Results obtained in this paper agree roughly with the physical constraints of the model given in /1/.