Trying to get this table to sort by default by "publish_date" Where can I ad it? 

    $transaction_params = array(
                              'posts_per_page' => $page_size,
                              'post_type' => 'realadv_transaction',
                              'post_status' => 'publish',
                              'exclude' => $used_transactions,
                              'suppress_filters' => false,
                              'tax_query' => array(
                                array(
                                  'taxonomy' => 'realadv_transaction_type',
                                  'field' => 'term_id',
                                  'terms' => $group['transaction_groups_types']->term_id,