Spectral Variation across Pulsar Profile due to Coherent Curvature Radiation

The pulsar profile is characterised by two distinct emission components, the core and cone. standard model of a radio beam originating from dipolar magnetic fields, places at centre surrounded concentric layers inner outer conal components. expected to have steeper spectra compared cones. We present detailed analysis relative differences in between large sample 53 pulsars over wide frequency range 100 MHz 10 GHz. was seen be much than cones particularly 1 GHz with difference spectral index $\Delta\alpha_{core/cone}\sim$ -1.0. In addition we also found components cone $\Delta\alpha_{in/out}\sim$ +0.5. flattening axis towards edge open field line region increasing curvature lines natural outcome coherent radiation charged soliton bunches, explains due relativistic beaming effect, only visible when it directed observer narrow angle $\theta\leq 1/\gamma$, where $\gamma$ Lorentz factor outflowing plasma clouds. This restricts cones, that are associated larger thereby making