A fracturing apparatus in a wellbore, having a housing with at least one injection port; an injection fluid supply interface to provide injection fluid for the hydraulic fracturing apparatus; and at least one high pressure combustor received within the housing. The housing further includes a combustible medium interface that is in fluid communication with the high pressure combustor, which is configured and arranged to provide repeated ignition cycles that include a combustion cycle that ignites the combustible medium and a fuel delivery cycle that delivers the combustible medium to the combustor, wherein pressure resulting from the combustion cycle forces the injection fluid out an injection port to cause fracturing in a portion of the earth around the wellbore.