  Cassiopeia A (Cas A) supernova remnant shows strong radiation from radio to
gamma-ray bands. The mechanism of gamma-ray radiation in Cas A and its possible
contribution to PeV cosmic rays are still under debate. The X-ray imaging
reveals an asymmetric profile of Cas A, suggesting the existence of a jet-like
structure. In this work, we propose an asymmetrical model for Cas A, consisting
of a fast moving jet-like structure and a slowly expanding isotropic shell.
This model can account for the multi-wavelength spectra of Cas A, especially
for the power-law hard X-ray spectrum from $\sim$ 60 to 220 keV. The GeV to TeV
emission from Cas A should be contributed by both hadronic and leptonic
processes. Moreover, the jet-like structure may produce a gamma-ray flux of
$\sim 10^{-13}\rm erg\ cm^{-2}\ s^{-1}$ at $\sim 100$ TeV, to be examined by
LHAASO and CTA.

High Energy Astrophysical Phenomena;Solar and Stellar Astrophysics