Speaker
Dr
Shuta Tanaka
(Institute for Cosmic Ray Research, The University of Tokyo)
Description
Pulsar winds have problems in energy conversion and pair-cascade processes which determine the magnetization, the pair multiplicity and the bulk Lorentz factor of the wind.
We study induced Compton scattering by a relativistically moving cold plasma to constrain wind properties by imposing that radio pulses from the pulsar itself are not scattered by the wind as was first studied by Wilson & Rees.
We find that relativistic effects cause a significant increase or decrease of the scattering coefficient depending on scattering geometry.
Applying the Crab pulsar wind, we obtain the lower limit of the bulk Lorentz factor of ~ 10 at the light cylinder when the wind velocity is significantly inclined with respect to the radio pulses.
Considering the lower limit of the pair multiplicity 10^6.6 suggested by recent studies of the Crab Nebula, the large inclination angle of the wind velocity (order unity), the small size of radio pulse emission region (~ 10^3 cm) and the small magnetization parameter (order unity) are required for the pair multiplicity > 10^6.6.
Author
Dr
Shuta Tanaka
(Institute for Cosmic Ray Research, The University of Tokyo)
Co-author
Prof.
Fumio Takahara
(Osaka University)
