Particle Acceleration and Pair Production in Pulsar Winds John Kirk - - PowerPoint PPT Presentation

▶
particle acceleration and pair production in pulsar winds
SMART_READER_LITE
LIVE PREVIEW

Particle Acceleration and Pair Production in Pulsar Winds John Kirk - - PowerPoint PPT Presentation

Mar 29, 2024 411 likes •638 views

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai Particle Acceleration and Pair Production in Pulsar Winds John Kirk Max-Planck-Institut fr Kernphysik

slide-1
SLIDE 1

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Particle Acceleration and Pair Production in Pulsar Winds

John Kirk

Max-Planck-Institut für Kernphysik Heidelberg, Germany Kinetic modelling of astrophysical plasmas, Krakow, 5th - 9th October 2008

slide-2
SLIDE 2

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Outline

1

Pair production in pulsars

2

Pair production in laser light

3

Particle trajectories in an E-M wave

4

Counter-propagating laser beams

5

Pair production in pulsar winds

slide-3
SLIDE 3

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Surface field B ∼ Bcrit = 4.4 × 1013 G

  • 3
  • 2
  • 1

1

  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
slide-4
SLIDE 4

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Surface field B ∼ Bcrit = 4.4 × 1013 G E · B = 0 acceleration → curvature radiation → single-photon pair production

  • 3
  • 2
  • 1

1

  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
slide-5
SLIDE 5

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Surface field B ∼ Bcrit = 4.4 × 1013 G E · B = 0 acceleration → curvature radiation → single-photon pair production Screening by pair-production front

  • 3
  • 2
  • 1

1

  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
slide-6
SLIDE 6

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Surface field B ∼ Bcrit = 4.4 × 1013 G E · B = 0 acceleration → curvature radiation → single-photon pair production Screening by pair-production front Multiplicity 104

  • 3
  • 2
  • 1

1

  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
slide-7
SLIDE 7

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Surface field B ∼ Bcrit = 4.4 × 1013 G E · B = 0 acceleration → curvature radiation → single-photon pair production Screening by pair-production front Multiplicity 104 Conflicts with PWN

  • bs.(de Jager 2007)

Time-dependent cascade models? (e.g., Timokhin, this workshop)

  • 3
  • 2
  • 1

1

  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
slide-8
SLIDE 8

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Accessible to Lab. experiment? Extraction from vacuum requires E > ESchwinger = 1.3 × 1018 V/cm Reached at laser intensity 2.3 × 1029 W/cm2 (Hope for 1023–1024 W/cm2 in 2009/2010)

slide-9
SLIDE 9

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Accessible to Lab. experiment? Extraction from vacuum requires E > ESchwinger = 1.3 × 1018 V/cm Reached at laser intensity 2.3 × 1029 W/cm2 (Hope for 1023–1024 W/cm2 in 2009/2010) But not possible in a single plane-wave

slide-10
SLIDE 10

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Accessible to Lab. experiment? Extraction from vacuum requires E > ESchwinger = 1.3 × 1018 V/cm Reached at laser intensity 2.3 × 1029 W/cm2 (Hope for 1023–1024 W/cm2 in 2009/2010) But not possible in a single plane-wave Pair production by electron requires η = γ B′

⊥

Bcrit ∼ 1

  • r, equivalently γE′

⊥/ESchwinger ∼ 1

(component of acceleration perp. to v important)

slide-11
SLIDE 11

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Figure-of-eight trajectory in linearly polarised wave Strictly periodic in a special reference frame (ZMF)

slide-12
SLIDE 12

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Figure-of-eight trajectory in linearly polarised wave Strictly periodic in a special reference frame (ZMF) If picked up at rest in lab. frame, particle recoils ZMF reached by boost in direction of wave, with Lorentz factor equal to (invariant) strength parameter: a = eB/mc 2πν

slide-13
SLIDE 13

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Figure-of-eight trajectory in linearly polarised wave Strictly periodic in a special reference frame (ZMF) If picked up at rest in lab. frame, particle recoils ZMF reached by boost in direction of wave, with Lorentz factor equal to (invariant) strength parameter: a = eB/mc 2πν Laser: a = 840

  • I24λµm,

Pulsar: a = 2.6 × 107

  • ˙

P15/P3rL/r

slide-14
SLIDE 14

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

E-M wave in ˆ z direction E along ˆ x E = −ˆ z × B Lorentz force vanishes for v → cˆ z No cancellation for periodic orbit, but B′ = B/a, so threshold is η ≈ γB′/Bcrit = (γ/a)B/Bcrit

slide-15
SLIDE 15

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Counter-propagating beams Pair production at node B = 0 Hot spot size ≈ λlaser Production via virtual photon dominates at η 0.5 For η > 0.8, cascade via real (curvature) photon Radiation reaction important for η > 0.5 Bell & Kirk arXiv:0808.2107

slide-16
SLIDE 16

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Current starvation in striped wind B ∝ 1/r, n ∝ 1/r2 Complete dissipation of Poynting flux impossible if κ < 2 × 103 ˙ P1/4

15 P−9/4

E-M wave in outer wind “Reflection” at termination “shock”?

  • 3
  • 2
  • 1

1

  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
slide-17
SLIDE 17

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Assume presence of a reflected wave Threshold ∝ γB ∝ 1/r2 Very rapid rise in production rate inside rthreshold Pair production possible if rthreshold > rL.

  • 3
  • 2
  • 1

1

  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
slide-18
SLIDE 18

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Assume presence of a reflected wave Threshold ∝ γB ∝ 1/r2 Very rapid rise in production rate inside rthreshold Pair production possible if rthreshold > rL.

  • 3
  • 2
  • 1

1

  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
slide-19
SLIDE 19

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Assume presence of a reflected wave Threshold ∝ γB ∝ 1/r2 Very rapid rise in production rate inside rthreshold Pair production possible if rthreshold > rL.

  • 3
  • 2
  • 1

1

  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
slide-20
SLIDE 20

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Conclusions

Kinetic modelling of laser plasmas closely related to kinetic modelling of astrophysical plasmas

slide-21
SLIDE 21

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Conclusions

Kinetic modelling of laser plasmas closely related to kinetic modelling of astrophysical plasmas Colliding laser beams expected to produce pairs in lab.

slide-22
SLIDE 22

Pair production in pulsars Pair production in laser light Particle trajectories in an E-M wave Counter-propagating laser beams Pai

Conclusions

Kinetic modelling of laser plasmas closely related to kinetic modelling of astrophysical plasmas Colliding laser beams expected to produce pairs in lab. Pair production in pulsar wind/wave cavity may be possible