1. the global pulsar magnetosphere
Particle simulations of
the global pulsar magnetosphere
Shinpei Shibata
Department of Phys.
Yamagata University
Collaborators:
Tomohide Wada and Shinya Yuki
School of Science and Technology,
Yamagata University

2. Rotation Power Pulsar wind magnetosphere Beamed radiation (gamma-ray)
Bulk acceleration, MHD
Kinetic energy + Poynting energy
Beamed radiation
(gamma-ray)
Particle acceleration by E//
magnetosphere
How two distinctive accelerations take place in the same magnetosphere.
Axisymmetric steady model
Special purpose computer for
Astrononomical N-body Problem

3. Pulsar Nebula Pulsar e+e- Wind
Observational facts:　Gaps and Wind
High energy and
radio pulsed emissions
Gamma-ray pulses
Pulsar
Wind
Polar Cap
e+e-
Outer Gap
Pulsar Nebula
Aim of particle simulation
Particle accelerator (～1013eV) in the magnetosphere
and
pulsar wind (γ～106 in bulk motion with Poynting flux)

4. Prospect: basic physics
Let us consider what happens around
the rotating neutron star in the vacuum
space.

5. Method of Solution 5. Free emission of particles
We iteratively solve the Maxwell equations and equation of motion with
1. Fields being axisymmetry, and steady:
2. Source magnetic field is dipole
3. the star is a perfect conductor, i.e.,
BC:
4. equation of motion with drag force
5. Free emission of particles
6. Pair creation if E//>Ec
Radiation reaction
Creation rate = factor x (E// /Ec)
7. Initial state: a star in vacuum

6. magnetic field
pair
creation
Step -1
dipole no
Step -2
Yes
(low rate)
Step -3
Modification by J
(high rate)

7. Result（１） Gap Formation
Step-1 Dipole field + no-pair creation
Magnetic field lines
electrons
Light cylinder
star
positrons

8. Result（１） Gap Formation
Step-1 Dipole field + no-pair creation
The final state is static clouds with the gaps (Krause-Polstorf and Michel 1985).
Light cylinder
electrons
Field-aligned Electric field
Gap
Gap
star
positrons

9. Result（2） Pair Creating Gap + wind Map of field-aligned electric field
electrons
Particle distribution
粒子分布
positrons
Outer gap
Outer Gap : pair creating region with E//
Outflow (equal amount of electrons and positrons are lost from the magnetosphere.
Both Gaps and wind are formed ! 9

10. Result（3） Pair Creating Gap + wind +
magnetic field modification
Map of
E/B
Magnetic field
Diple field
Open magnetic flux
Dissipataive
Current sheet
E>B
Udzdensky 2003

11. summary
Strong charge separation by emf of the star produces the outer gaps.
The gaps persist and create pairs providing the particle source of the pulsar wind.
If pair creation rate is high, then magnetic field is opened and pairs flow out along the open magnetic flux. This is the pulsar wind.
If pair creation rate is low, then the wind is moderate, and some particles circulate in the magnetosphere with strong radiation drag (high Lorentz factor).