  Based largely on energy budget considerations and the observed cosmic-ray
(CR) ionic composition, supernova remnant (SNR) blast waves are the most likely
sources of CR ions with energies at least up to the "knee" near 3 PeV. Shocks
in young shell-type TeV-bright SNRs are surely producing TeV particles, but the
emission could be dominated by ions producing neutral pion-decay emission or
electrons producing inverse-Compton gamma-rays. Unambiguously identifying the
GeV-TeV emission process in a particular SNR will not only help pin down the
origin of CRs, it will add significantly to our understanding of the diffusive
shock acceleration (DSA) mechanism and improve our understanding of supernovae
and the impact SNRs have on the circumstellar medium. In this study, we
investigate the Vela Jr. SNR, an example of TeV-bright non-thermal SNRs. We
perform hydrodynamic simulations coupled with non-linear DSA and
non-equilibrium ionization near the forward shock (FS) to confront currently
available multi-wavelength data. We find, with an analysis similar to that used
earlier for SNR RX J1713.7-3946, that self-consistently modeling the thermal
X-ray line emission with the non-thermal continuum in our one-dimensional model
strongly constrains the fitting parameters, and this leads convincingly to a
leptonic origin for the GeV-TeV emission for Vela Jr. This conclusion is
further supported by applying additional constraints from observation,
including the radial brightness profiles of the SNR shell in TeV gamma-rays,
and the spatial variation of the X-ray synchrotron spectral index. We will
discuss implications of our models on future observations by the
next-generation telescopes.
