peaeater

<fieldType name="alphaNumericSort" class="solr.TextField" sortMissingLast="false" omitNorms="true">
  <analyzer>
    <!-- KeywordTokenizer does no actual tokenizing, so the entire
         input string is preserved as a single token
      -->
    <tokenizer class="solr.KeywordTokenizerFactory"/>
    <!-- The LowerCase TokenFilter does what you expect, which can be
         when you want your sorting to be case insensitive
      -->
    <filter class="solr.LowerCaseFilterFactory" />