The May 1997 and May 1998 MURI events George H. Fisher UC Berkeley
May Classic 2-ribbon flare occurring in NOAA AR 8038 at ~ 04:45 UT Halo CME seen ~ 1-2 hours later (partial) filament eruption Global solar magnetic configuration is quite simple Magnetic data: poor temporal coverage, coarse spatial resolution In MURI teams: Yang Liu (Stanford) is doing most of the work on this event
Global magnetic configuration around May 12, 1997 (pfss model) Overall global magnetic configuration is simple; just one active region on the disk at the time of the flare/CME.
Magnetic Evolution of AR 8038 over 3 days: Active region appears to be mature and starting to decay, with apparent flux cancellation …
May 12, 1997: Evolution seen in H 2-ribbon flare Partial filament disappearance X-ray importance: C-class
May : X-ray evolution: Before flare: sigmoid shaped arcade Flare decay: classic candle- flame shaped arcade
May 12, 1997: Double dimming, EIT wave Double- dimming occurs after flare, roughly at ends of 2- ribbon flare arcades.
May : LASCO C2 images Wimpy halo event seen ~ 2 hours after the 2-ribbon flare
Interplanetary Data for the May event Some hidden text
May 1, 1998 Active region 8210 produced a long series of flares and CMEs as it rotated across the disk. Our focus is several small flares / CMEs occurring on May 1, 1998 because of very high quality vector magnetic field observations taken that day. Overall solar configuration was not so simple: 8210 appears connected to an active region across the equator via trans-equatorial loops
Global magnetic configuration around May 1, 1998 (pfss model) AR 8210 appears to be magnetically connected to a northern hemisphere AR and is also adjacent to a low-latitude coronal hole…
24 hours of high cadence MDI evolution of AR 8210 on May : Flux emergence above and to right of sunspot Clockwise rotation of sunspot Flow of positive polarity on left of spot toward lower right
Non-constant force-free field fit to AR 8210 (Regnier) Uses vector magnetogram data from IVM instrument on Haleakala – data averaged for a 15 minute cadence
Models of the emission from AR 8210 (Loraine Lundquist) Start from Regnier’s FFF solution Assume a heating function Q ~ B/L on each field line Solve energy balance equation Compute emissivity and make false image
H evolution of AR8210 on May 1, 1998 There are several filaments associated with this active region, which appear to be constantly evolving There appears to be a 2-ribbon flare around 23:40 UT
X-ray evolution of AR 8210 on May 1, 1998 Note simultaneous flickering of the two active regions, plus hint of transequatorial loops Note the repeated activation of the arcade of loops on the LHS of the active region
EIT evolution of AR 8210 on May 1, 1998 Note repeated brightenings along LHS of active region adjacent to “coronal hole” This evolution described by Sterling & Moore in their paper on EIT “crinkles” as repeated reconnection of closed field lines with open field lines in the hole
Interplanetary Data for May 1, 1998