[TYPO3-Solr] API-Use change search from and to or

[Heiko Kromm | Paints]

Hi List, 

I created a search with the api: 
$search = t3lib_div::makeInstance('tx_solr_Search'); 
$query = t3lib_div::makeInstance('tx_solr_Query', $searchkey); 
$search->search($query); 
$response = $search->getResponse(); 

In $searchkey could be multiple keywords and I want solr to search for all documents containing any of the words (OR). 
Is ist possible to change search behavior from AND to OR? 

Regards 
Heiko