The page http://www.datastax.com/docs/datastax_enterprise3.0/solutions/dse_search_upload explains how to reload a solr core. It mentions a curl call:
curl http://localhost:8983/solr/admin/cores?action=RELOAD&name=<keyspace.columnfamily>
--reindex=true --deleteAll=false
which should (probably) really be
curl "http://localhost:8983/solr/admin/cores?action=RELOAD&name=<keyspace.columnfamily>&reindex=true&deleteAll=false"
