Caustic Model for High-Energy Lightcurves of Pulsars

We present a new model of high-energy lightcurves from rotation powered pulsars. The model is based on a minimal number of assumptions. The generic features of the model are consistent with the observed characteristics of pulsar lightcurves: 1) the most natural (in terms of probability) shape consists of two peaks (separated by 0.4 to 0.5 in phase for large viewing angles); 2) the peaks posess well developed wings; 3) there is a bridge (inter-peak) emission component; 4) there is a non-vanishing off-pulse emission level; 5) the radio pulse occurs before the leading peak. We also discuss the optical polarization properties for the Crab pulsar in the context of the caustic model. We suggest that successful physical models of high-energy pulsars would include the properties outlined in our caustic model. Subject headings: pulsars: high-energy radiation, lightcurves