Silicate grain growth due to ion trapping in oxygen-rich supernova
  remnants like Cassiopeia A
  Core-collapse supernovae can condense large masses of dust post-explosion.
However, sputtering and grain-grain collisions during the subsequent passage of
the dust through the reverse shock can potentially destroy a significant
fraction of the newly formed dust before it can reach the interstellar medium.
Here we show that in oxygen-rich supernova remnants like Cassiopeia A the
penetration and trapping within silicate grains of the same impinging ions of
oxygen, silicon and magnesium that are responsible for grain surface sputtering
can significantly reduce the net loss of grain material. We model conditions
representative of dusty clumps (density contrast $\chi=100$) passing through
the reverse shock in the oxygen-rich Cassiopeia A remnant and find that,
compared to cases where the effect is neglected, as well as facilitating the
formation of grains larger than those that had originally condensed, ion
trapping increases the surviving masses of silicate dust by factors of up to
two to four, depending on initial grain radii. For higher density contrasts
($\chi\gtrsim180$), we find that the effect of gas accretion on the surface of
dust grains surpasses ion trapping, and the survival rate increases to
${\sim}55 \%$ of the initial dust mass for $\chi=256$.
