<?php

$client = new Solarium_Client;
$client->setHost('127.0.0.1');
$client->setPort(8983);
$client->setPath('/solr/');
$client->setCore('core0');

$query = new Solarium_Query_Ping;
$result = $client->ping($query);

// this will be 200 in case of a succesful ping
echo $result->getStatus();