1. A brief introduction- Outer gap model of r-ray pulsar Department of Physics National Tsing Hua University Lun-Wen Yeh 2003.5.15

2. The basic structure of the magnetosphere The basic structure of the magnetosphere Outer gap model Outer gap model Then …… Then …… Reference: 1.K.S.Cheng,C.Ho,M.Ruderman.1986,ApJ 2.V.S.Beskin,A.V.Gurevich,Ya.N.Istomin Physics of the pulsar magnetosphere.

3. The basic structure of the magnetosphere If the neutron star is a rotating magnetosphere with magnetic dipole moment. If the neutron star is a rotating magnetosphere with magnetic dipole moment. We assume the star which is perfect conductor. We assume the star which is perfect conductor. In the interior: In the interior: J=σ(E +v × B/c) E=-v × B/c J=σ(E +v × B/c) E=-v × B/c E·B=0 E·B=0 In the outside: In the outside: If it is vacuum E·B≠0 If it is vacuum E·B≠0 However E·B would exceed the component of the for gravitational force for an electron or a proton. However E·B would exceed the component of the for gravitational force for an electron or a proton. A rotating magnetic neutron star can not be surrounded by a vacuum!! A rotating magnetic neutron star can not be surrounded by a vacuum!! E · B≠0 E · B=0 ＾

4. The region surrounding the star is filled with plasma. We assume the plasma corotating with the neutron star as a rigid body. The region surrounding the star is filled with plasma. We assume the plasma corotating with the neutron star as a rigid body. E=-v × B/c (the same with the inside) E=-v × B/c (the same with the inside) ρ 0 = ( ▽ ·E)/4π=-Ω·B/2 πc [1-(Ωrsinθ /c) 2 ] ρ 0 = ( ▽ ·E)/4π=-Ω·B/2 πc [1-(Ωrsinθ /c) 2 ] B ~ [3(m·r)r-m]/r 3 B ~ [3(m·r)r-m]/r 3 ＾ ＾

5. figure1

6. n c = ρ 0 /e (particle/cm 3 ) n c = ρ 0 /e (particle/cm 3 ) n c ~10 -6 (particle/cm 3 ) for earth n c ~10 -6 (particle/cm 3 ) for earth n c ~10 -5 (particle/cm 3 ) for Jupiter n c ~10 -5 (particle/cm 3 ) for Jupiter n c ~10 11 ~10 12 (particle/cm 3 ) for neutron star n c ~10 11 ~10 12 (particle/cm 3 ) for neutron star B~10 12 G B~10 12 G R~10 6 cm=10km R~10 6 cm=10km In the open field region there have flowing-current. In the open field region there have flowing-current.

7. Outer gap model In order to explain r-ray pulsar In order to explain r-ray pulsar polar cap polar cap outer gap (1986 Cheng, Ho, Ruderman) outer gap (1986 Cheng, Ho, Ruderman) We assume the current which flow through null-surface and result in the charges depletion in this region. We assume the current which flow through null-surface and result in the charges depletion in this region. In the gap E·B≠0 such that e± production mechanisms would create a pair plasma. In the gap E·B≠0 such that e± production mechanisms would create a pair plasma. Curvature radiation Curvature radiation Inverse Compton scattering Inverse Compton scattering Synchrotron radiation Synchrotron radiation ＾

8. figure2

9. figure3

10. For the Crab and Vela pulsar most observes would detect two r-ray pulsars per period. For the Crab and Vela pulsar most observes would detect two r-ray pulsars per period. See See 1.Path difference 1.Path difference 2.Field bending 2.Field bending 3.Aberration 3.Aberration Two or Four Two or Four 1.Thickness 1.Thickness 2.Dip angles 2.Dip angles

11. figure4

12. figure5