Synchronous Physical Properties Of The Curvature Radiation Mechanism

The synchron-curvature mechanism solves the radiation problem of relativistic particles moving in a curved magnetic fields. This mechanism has already been applied in many astrophysics sources including pulsar, GRBs and AGNs. In this paper, according to the synchron-curvature radiation theory, we successful fit the spectrums of GRB, and discuss the radiation properties of the charged particles moving in a gerenal curved magnetic fields. Then we study the maser phenomenon under plasma condition also including the effects of the drift of charged particles. Finally we discuss some potential applications of these results.It is possible to research the radiation properties of the relativisitic charged particles precisely in astrophysical magnetic field, since the synchron-curvature radiation mechanism was discovered. In Chapter 1, we briefly go over the synchrotron radiation mechanism and curvature radiation mechanism, then we introduced the synchro-curvature radiation mechanism. With respect to the radiation of power law energy distribution of electrons, which is of great importance in astrophysics, we demonstrate that their synchro-curvature radiation spectrum is no longer simple power law. The low frequency and high frequency segments are approximately similar to that of synchrotron and curvature process respectively, and both segments are connected smoothly. The flatness in the higher frequency spectrum is due to the effect of the curved magnetic field lines and can well interpret the abnormal continuum in their spectra observed in some cosmic sources. Regarding the realistic magnetic fields widely exist in various cosmic sources, especially that formed behind the shock, although we still have no any idea of the formation process, the treatment in the uniform fields is definitely not correct. Our formula for the non-uniform fields are helpful for studying the problem. In 1998, Yuan and Zhang obtained the quantized formula of synchron-curvature radiation mechanism, these quantized formula is an important development section of the whole synchron-curavture theory.In Chapter 2, We also briefly introduce the high energy radiation process of pulsars and three famous radiation models for γ ray pulsars: (1)Polar Gap Model, (2)Out Gap Model, (3) Slot Gap Model. Although many kinds of pulsar model are different with each other and none of them can explain the radiation from the 7 ray pulsars completely, but almost all kinds of models have a common characteristics, for example, a strong electric field exists in the magnetphere of pulsars and the magnetic field is assumed to be a curved dipole magnetic field. So it will be not precise if we discuss the radiation process of pulsars with synchrotron radiation or cyclotron radiation, but the synchron-curvature radiation can solve the curvature effect of the magnetic field very well. In Chapter 3, we give a brief introduction to GRB physics, especially the well-accepted fireball-shock model. GRB is a phenomenon of a short time scale burst of Gamma ray. Most of the radiation energy of the GRB is between 30Kev and 10Mev, some small amount of energy powers their afterglow. By analysing the spectrum of the GRB, we can understand the radiation mechanism of GRBs and the central engine of GRBs.Our works are included in Chapter 4-6. In Chapter 4, we discuss the fault of the fireball shock model. Although this model can demonstrate the gerenal process of the GRBs and can explain most of the properties of the GRBs' afterglow, but in this model, the radiation is generally regarded as synchrotron radiation. This viewpoint may be wrong and may be cause the recent difficulty of explaining the update observations. We discovered that the synchron-curvature radiation mechanism can fit a series of spectra of GRBs very well. We can explain the high energy inflexion and energy surplus which can not be explained by synchrotron mechanism. This means that the magnetic fields of GRBs is curved and can not satisfy the requirements of synchrotron radiation. So the synchron-curvature theory is a good choice for GRBs. According to our results, we establish a possible magnetic field form of GRBs and discuss the formation of this magnetic field form. After we analyse the spectrums of GRBs which is fitted by synchron-curvature radiation mechanism, we find out a constrain of the acceleration of the shock of the GRBs. All these things help us realize that the synchron-curvature radiation mechanism can be widely applied in astrophysics.In chapter 5, we research both the self-absorption properties of the synchron-curvature radiation and the maser phenomenon. Neglecting the curvature drift (we will talk about the effect of drift in Chapter 6), Blandford(1975) had proved that the curvature maser emission is impossible. It has been found out that maser is impossible in vacuum (if the effects of the drift of the guiding center are neglected (Yang 2003)). We find that although the synchron-curvature process has no maser action in vacuum, the effects of plasma can cause maser action according to our theorectical analysis and calculations. As the power radiated by synchron-curvature mechanism is substantially greater than that of synchrotron one, the maser of the synchron-curvature mechanism could be more powerful than that of the synchrotron one, which maybe helpful for the solution of the extreme temperature trouble in various radio sources.In chapter 6, we consider the drift effect of the charged particles, which is moving along the curved magnetic field. Including the drift of their the guiding center, we show that the maser emission is possible even in vacuum. The unified synchro-curvature mechanism(Zhang&Cheng 1995; Cheng&Zhang 1996), if without drift, can be developed further because such kind of magnetic field will create a magnetic gradient, which gener- ates some kinds of force and then cause the drift motion of the particles. Sometime, this effect can give a non-negligible contribution to the radiation spectrum (Harko&Cheng 2002). As the magnetic field of GRBs is curved, if we consider the synchro-curvature maser including the drift, we are sure that the values of the ξ_e and ξ_b will be different from the ones if only the synchrotron radiation is considered. These effects may serve as an important clue to the GRB environment and their progenitor.