  The reverse shock of supernova remnant (SNR) 1987A emits in H-alpha and
Ly-alpha, and comes in two flavors: surface and interior. The former is due to
direct, impact excitation of hydrogen atoms crossing the shock, while the
latter is the result of charge transfer reactions between these atoms and
slower, post-shock ions. Interior and surface emission are analogous to the
broad- and narrow-line components observed in Balmer-dominated SNRs. I
summarize a formalism to derive line intensities and ratios in these SNRs, as
well as a study of the transition zone in supernova shocks; I include an
appendix where I derive in detail the ratio of broad to narrow H-alpha
emission. Further study of the reverse shock emission from SNR 1987A will allow
us to predict when it will vanish and further investigate the origins of the
interior emission.
