An evaluation of electron-photon cascades developing in matter, photon and magnetic fields

Electromagnetic cascades in matter, photon fields, and magnetic fields are solved by a standard numerical method, integrating the diffusion equations of respective cascade processes numerically. Our results and those of Aharonian and Plyasheshnikov agree very well for cascades in matter and magnetic fields, though they show some slight discrepancies for cascades in photon fields of high incident energies. Transport properties of electron and photon spectra are also investigated by solving differential-difference equations for cascades with simplified cross-sections, and the spectra under the electron cooldown process are well explained quantitatively.