Gradient of Magnetic Field in Pulsar Star
**Department of astronomy, College of Science, University of Baghdad. Baghdad-Iraq
The magnetic field of pulsar (B), is considered to be magnetic dipole field. The pulsar is a neutron star. The pulsar magnetic field is about (108 T), with high if curvature and radius or ( 104 m). The work is interested on the geometry of the magnetic field within the light cylinder (RL =3x108m).The model of pulsar, which we adopted, is that of (Goldriech & Julian), the dipole axis is in the same axis of the star rotation it is an aligned rotator. Within this consideration we studied the types or gradient with changing position angle (λ) The first type, -B-Grudien in (r) direction (∇rB), and the second type,-B- Gradient in (λ) direction (∇λB). The results indicated that the assumed magnetic field configuration enable us to estimate, why the two types of Grad.-B, increase towards the limits of the light cylinder. Therefore we noted the magnetic field inside the light cylinder is very strong with high curvature for star surface. Also, we concluded, after the boundary of (RL), the magnetic field lines are open and the charges will be accelerate with high velocity and flow out the light cylinder.