210 likes | 386 Views
CRITICAL FIELDS IN PHYSICS AND ASTROPHYSICS ``DYADOSPHERE’’. Electron-positron production, annihilation, oscillation and thermolization in super-critical electric field. 2) ``Melting’’ phase transition: the nucleon matter core, nuclei matter surroundings.
E N D
CRITICAL FIELDS IN PHYSICS AND ASTROPHYSICS ``DYADOSPHERE’’ • Electron-positron production, annihilation, oscillation and thermolization in • super-critical electric field. • 2) ``Melting’’ phase transition: the nucleon matter core, nuclei • matter surroundings. • 3) Super-critical electric field on the surface of collapsing core. • 4) Electron-positron-photon plasma (dyadosphere) formed in • gravitational collapses. • 5) Hydrodynamic expansion of Electron-positron-photon plasma. She-Sheng XUE ICRANet, Pescara, Italy To understand How the gravitational energy transfers to the electromagnetic energy for Gamma-Ray-Bursts.
E ~ 1054 ergs T ~ 1 sec.
Step 1 External layersof nuclei matter electrically neutral Melting density Nucleon matter phase Nuclei matter phase Super-critical electric field and charge-separation on the surface of massive collapsing core of nucleon matter. Charge separation Supercritical field
Density proton Fermi-energy in nuclei matter Fermi-energy (MeV) proton Fermi-energy in nucleon matter ``We see that the slops of the two curves are quite different, indicating a sharp transition... Thus, at the crossing point the nuclei will melt and cease to exist. This melting is completely sharp…within a one-percent of density change.’’ Bethe, Borner and Sato, 1971
Supercritical field on the surface of massive nuclear cores Degenerate protons and neutrons inside cores are uniform (strong, electroweak and gravitational interactions): -equilibrium Degenerate electrons density Electric interaction, equilibrium electric Poisson equation for Thomas-Fermi system for neutral systems
Super Heavy Nuclei surface Neutron star cores surface (in Compton unit) Ruffini, Rotondo and Xue (2006,2007,2008)
Step-2 Black hole Dyadosphere(electron-positron and photon plasma outside the collapsing core)
Gravitational Collapse of a Charged Stellar Core Equation Solution: De la Cruz, Israel (1967); Boulware (1973); Cherubini, Ruffini, Vitagliano (2002) This gives the rate of gravitational collapsing, and we can obtain the rate of opening up phase-space for electrons.
t + + + + + + + + R Pair creation during the gravitational collapse of the massive charged core of an initially neutral star. It will be shown that the electric field is magnified by the collapse to E > Ec , ….
f distribution functions of electrons, positrons and photons, S(E) pair production rate and collisions: Polarization current Conduction current What happens to pairs, after they are created in electric fields? A naïve expectation !!! Vlasov transport equation: And Maxwell equations (taking into account back reaction) Ruffini, Vitagliano and Xue (2004)
Results of integration(integration time ~ 102tC) • Discussions: • The electric field strength as well as the pairs oscillate • The role of the scatterings is negligible at least in the first phase of the oscillations • The energy and the number of photons increase with time Ruffini, Vitagliano and Xue (2004) Ruffini, Vereshchagin and Xue (2007) Electric energy to pair numbers to pair’s kinetic energy
Time and space scale of oscillations • The electric field oscillatesfor a time of the order of rather than simply going down to 0. • In the same time the electromagnetic energy is converted into energy of oscillating particles • Again we find that the microscopic charges are locked in a very small region: compared with gravitational collapse time-space scale Phase-space and Pauli blocking Ruffini, Vitagliano and Xue (2005)
E Emax Ec r+ rdya r A specific Dyadosphere example Edya Electron-positron-photon plasma (Reissner-Nordstrom geometry) G. Preparata, R. Ruffini and S.-S. Xue 1998
External layers of nuclei matter Step-3 Black hole Electron-positron-photon plasma expansion, leading to GRBs
Aksenov, Ruffini Vereshchagin(2007) Thermal equilibrium t Already discussed Plasma oscillations Core collapsing, plasma formation and expansion R Ruffini, Salmonson, Wilson and Xue (1999) Ruffini, Salmonson, Wilson and Xue (2000)
The redshift factor a encodes general relativistic effects Equations of motion of the plasma (I) Part of the plasma falling inwards (II) Part of the plasma expanding outwards Ruffini, Vitagliano and Xue (2004)
The existence of a separatrix is a general relativistic effect: the radius of the gravitational trap is The fraction of energy available in the expanding plasma is about 1/2
Predictions on luminosity, spectrum and time variability for short GRBs. (1) The cutoff of high-energy spectrum (2) Black-body in low-energy spectrum (3) Peak-energy around ~ MeV Fraschgetti, Ruffini, Vitagliano and Xue (2005)
(4) soft to hard evolution in spectrum (5) time-duration about 0.1 second Fraschgetti, Ruffini, Vitagliano and Xue (2006)