SheSheng XUE - PowerPoint PPT Presentation

Title: SheSheng XUE


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CRITICAL FIELDS IN PHYSICS AND ASTROPHYSICS OF
NEUTRON STARS AND BLACK HOLES
Research topics
1) Electron-positron production, annihilation and
oscillation in super-critical electric field.
2) Super-critical electric field on the surface
of collapsing core. 3)
Electron-positron-photon plasma formed in
gravitational collapses. 4) Hydrodynamic
expansion of Electron-positron-photon plasma.
To understand
how the gravitational energy transfers to the
electromagnetic energy for Gamma-Ray-Bursts.

• She-Sheng XUE
• ICRANet, Pescara, Italy

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International and ICRANet Participants
F. Fraschetti (CEA Saclay,
France) H. Kleinert (Free
University of Berlin , Germany R. Klippert
(ICRANet, Brazile) G. Preparata
(INFN, University of Milan, Italy) V. Popov
(ITEP, Moscow, Russia) R.
Ruffini (ICRANet, University
of Rome, Italy) J. Salmonson
(Livemore National Lab., University of
California, USA) L. Vitagliano
(ICRANet, University of Salerno, Italy) G.
Vereshchagin (ICRANet, Minsk, Belarus) J.
Wilson (Livemore National Lab.,
University of California, USA) S.-S. Xue
(ICRANet)
PhD and MS Students
G. De Barros L. J. Rangel Lemos B. Patricelli J.
Rueda M. Rotondo
passed away
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E 1054 ergs
T 1 sec.
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External layersof the star
Super-critical electric field and
charge-separation on the surface of massive
collapsing core
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Black hole
Dyadosphere(electron-positron and photon plasma
outside the collapsing core)
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External layers of the star
Black hole
Electron-positron-photon plasma expansion,
leading to GRBs
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The Black hole energyE2 (Mirc2 Q2/2r)2
(Lc/r)2 p2
Christodoulou, Ruffini, 1971
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Electron-positron pairs production and Dyadosphere
Heisenberg
Damour
The Dyadosphere electron-positron-photon plasma
of size 108 cm, temperature 10MeV, and total
energy 1051-54 ergs. G. Preparata, R. Ruffini
and S.-S. Xue (1998)


Ruffini
Preparata
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A specific Dyadosphere example
Edya
Electron-positron-photon plasma
(Reissner-Nordstrom geometry)
G. Preparata, R. Ruffini and S.-S. Xue 1998
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(Kerr-Newmann geometry)
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A general formula for the pair-production rate in
non-uniform fields
in collisions of laser beams and heavy ions,
neutron stars and black holes.
Kleinert
(Kleinert, Ruffini and Xue 2007)
Confined (Sauter) field
Coulomb field and bound states
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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)
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• Results of numerical integration
  (integration time 102 tC)
• 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)
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Conclusions

• The electric field oscillates for 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

Ruffini, Vitagliano and Xue (2005)
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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
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Popov
Super Heavy Nuclei
surface
Neutron star cores
surface
(in Compton unit)
Ruffini, Rotondo and Xue (2006,2007,2008)
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Gravitational Collapse of a Charged Stellar Core
De la Cruz, Israel (1967) Boulware
(1973) Cherubini, Ruffini, Vitagliano (2002)
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An Astrophysical Mechanism of Electromagnetic
Energy Extraction
Pair creation during the gravitational collapse
of the masive charged core of an initially
neutral star.
If the electric field is magnified by the
collapse to E gt Ec , then
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An Astrophysical Mechanism of Electromagnetic
Energy Extraction
R
Ruffini, Salmonson, Wilson and Xue
(1999) Ruffini, Salmonson, Wilson and Xue (2000)
Wilson
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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)
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The fraction of energy available in the
expanding plasma is about 1/2
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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)
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(4) soft to hard evolution in spectrum (5)
time-duration about 0.1 second
Fraschgetti, Ruffini, Vitagliano and Xue (2006)