Elasticsearch 5.x Full Text Regular Expression

Question

New to ELK, trying to find a full text search with regular expression, I create a test index

  {"test_monitoring":
    {"aliases":{}
    ,"mappings":
      {"messagerie":
        {"properties":
          {"header":
            {"type":"text"
             ,"fields":
              {"keyword":
                {"type":"keyword","ignore_above":256
     } } } } } }
    ,"settings":
      { "index":
        { "creation_date":"1490005518469","number_of_shards":"5","number_of_replicas":"1","uuid":"f8AsV6OrQEqx7_-HoEYxwA","version":
          { "created":"5020299"}
        ,"provided_name":"test_monitoring"
  } } } }

therefore the property "header":

• text
• keyword

allowing a normal full-text search, and not just a token with an account

Entering 1 record (data after get)

hits|total                      | 1
    |max_score                  | 1.0
    |0|_index                   | "test_monitoring"
    | |_type                    | "messagerie"
    | |_id                      | "1"
    | |_score                   | 1.0
    | |_source|header           | "La pomme d adan n est pas utile a la mastication"

I can do a search with:

"query": { "match": {
      "header" : "pomme"
      }    }

or "header.keywork" : "La pomme d adan n est pas utile a la mastication"

but never a regular expression with more than 1 word will hit something [no error, full _shard, ...] (ok for header.keyword, but the title is the text "not_analyzed", which understands the new ELK version New text / line behavior / keyword

GET /test_monitoring/messagerie/_search
{  "query":  {
        "regexp" :{
            "header" : "la.*pom*e"
}   }   }   }

, , "not_analyzed" , , not_analyzed text

PUT /test_monitoring/messagerie/_mapping
{
"messagerie": {
  "properties": {
    "header": {
      "type": "text",
      "fields": {
        "keyword": {
          "type": "keyword",
          "ignore_above": 256
          }
        , "as_text_na" : {
          "type" : "text"
          , "index" : "not_analyzed"
          }
        }
      }
    }
  }
}

:

, , ? , , .