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WGC: Evolutionary Context of CMEs and ARs – Wed PM Magnetic field projects. According to nonlinear force-free field models AR10989 had the weakest field, least free magnetic energy and least relative helicity . Yet 10989 was the most active. AR 10987
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WGC: Evolutionary Context of CMEs and ARs – Wed PMMagnetic field projects
According to nonlinear force-free field models AR10989 had the weakest field, least free magnetic energy and least relative helicity. Yet 10989 was the most active.
AR 10987 Net flux = 1.68×1017Mx - 3.46×1017Mx = -1.78×1017Mx Energy = 1.074x1027 ergs = 1.055 Epot Helicity = -4.06x1031 Mx2 or -3.94x1031 Mx2 E E W W α = 0 α = αmag
AR 10988 Net flux = 2.39×1017Mx – 1.26×1017Mx = 1.13×1017Mx Energy = 1.070x1027 ergs = 1.024 Epot Helicity = 8.19x1031 Mx2 or 6.25x1031 Mx2 E E W W α = 0 α = αmag
AR 10989 Net flux = 1.56×1017Mx – 1.34×1017Mx = 2.18×1016Mx Energy = 3.05x1026 ergs = 1.0005 Epot Helicity = -1.12x1031 Mx2 or -1.12x1031 Mx2 E E W W α = 0 α = αmag
On the Cause and Nature of the Eruptions in AR 10989 Sterling, IAU talk, 2009
MDI on EIT: 30 March Eruption Crinkles? (Sterling & Moore 2001)
Use models, McIntosh's H-alpha maps, STEREO coronagraph and EUV data to determine the relationship between prominences/active regions,coronal holes, streamers, and CMEs on Dave’s long list.Possibly calculate field lines that open up as a result of a CME using PFSS models.
McIntosh’s Hα synoptic charts show long-lived trans-equatorial filament at about 240 deg longitude, roughly coinciding with warp in streamer belt.
Welsch's feature tracking of surface flows characterizes active region photospheric dynamics. Little sign that AR10989 should be the most active.
AR 10988 and 10987 had the highest proxy Poynting fluxes. AR 10989 should have been least active.
I made a preliminary analysis of the amount of flux cancelled in each AR. • For two features to be defined as cancelling over a given dt, I required: • features to posses adjacent pixels • their centers of flux to approach • their fluxes to decrease. • A (lower-limit) estimate of cancelled fluxes: • AR 10987: ~ 5 x 1020 Mx • AR 10988: ~ 8 x 1020 Mx • AR 10989: ~ 3 x 1020 Mx Less flux cancelled in AR 10989 than in the other ARs.
What about other indicators of flare activity? Leka & Barnes (2007) found to be a strong flare predictor. Here, too, AR 10989 should be the least active.
As with other measures known to be associated with flares, R in 10988 and 10987 exceeded that in 10989. Again, AR 10989 should have been least active.
The cumulative helicity flux in 989 roughly matches that in 988, though the latter has more magnetic flux. Hence, the helicity per unit flux in 989 exceeds that in 987 & 988. Is this why it’s more active?
According to NLFFF modeling and feature tracking • AR10987 –vehelicity, +vehelicity change • AR10988 +vehelicity, -vehelicity change • AR10989 –vehelicity, -vehelicity change
Subsurface kinetic helicity maps from Rudi Komm: alternating signs kinetic helicity?
Photospheric twist w/o Helicity* • Tube crosses photosphere • Helicity is transported into • coronal field • Current in coronal field • matches twsit in flux tube • Begin w/ straight untwisted tube • (H=0) • External flows induce LH writhe • (dH/dt =0) • Coupling term SRH twist Longcope, IAU talk, 2003) * From the emergence of a flux tube with no net helicty
Consistent with NLFFF models’ large flux imbalances, the three active regions are highly interconnected in PFSS models. All lie near boundaries between open and closed field, particularly 10987 & 9.