Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Ground Event / Encounter Loss Of Aircraft Control
Flight Crew Regained Aircraft Control
Environment - Non Weather Related; Procedure; Airport
We were in position and hold on runway 22L at ORD; a B777 was lined up on 28R full length.  The B777 was cleared for takeoff on 28R and about 20 seconds later we were cleared for takeoff on 22L.  We were very light and the aircraft accelerated quickly. We encountered the jet blast from the B777 just at the 80 knot call which caused our aircraft to yaw violently to the right about 20 degrees off runway heading and slid about a plane's width across the runway. Quick action by the First Officer corrected the yaw deviation and the aircraft was brought back under control and straightened out. The takeoff was continued with no further problems. In retrospect I should have probably called an abort but the the reaction to recovery was so short by the time I thought about it we were already back under control and there was no longer the need to abort. ATC never cautioned us of the jet blast but had cautioned an aircraft landing on 28L about the heavy taking off 28R.Suggestions: To avoid this in the future I will not accept a takeoff clearance; nor should one be given after the launch of heavy jet off a runway that has the jet blast crossing your takeoff runway without sufficient time for the blast to dissipate.  This unique geometry of the 2 runways at ORD should be treated in the same manner as we do wake turbulence.  This should also apply to any other airport runway configuration with a similar geometry.  The aircraft on runway that would get the jet blast should always be cleared for takeoff first prior to have the other aircraft especially a heavy receive takeoff clearance; or an appropriate delay is required.  The other would be a blast fence erected between the 2 runways. If an aircraft was landing on 22L with the same scenario and encountered the jet blast in the flare it could easily cause a loss of control and an aircraft accident.
CRJ-200 Captain reported directional control difficulties on takeoff roll on ORD Runway 22L when they encountered jet blast from a B777 on takeoff from Runway 28R.