July 21, 2002



20020721.175223_mk4

Center =316.85+/-0.96 degrees PA (NW quadrant) (red radial line)
Maximum height = 1.32+/-0.01 Rsun
Width (at 1.20 Rsun) = 10.14+/-0.97 degrees latitude (measured between edges -- vertical dashed lines at inflection points)
Width (at 1.26 Rsun) = 6.82+/-0.94 degrees latitude
Cavity depletion, equatorward (1.20 Rsun) = 0.24+/-0.015 (ratio of red to blue dashed line)
Cavity depletion, equatorward (at 1.26 Rsun) = 0.21+/-0.016 (ratio of red to blue dashed line)
Cavity depletion, poleward (1.20 Rsun) = 0.19+/-0.016 (ratio of green to blue dashed line) Minimum intensity in cavity (1.20 Rsun) = 2.6e-07+/-2.6e-09 (Bsun) (blue dashed lines);
Cavity depletion, poleward (1.26 Rsun) = 0.17+/-0.017 (ratio of green to blue dashed line) Minimum intensity in cavity (1.26 Rsun) = 2.4e-07+/-2.4e-09 (Bsun) (blue dashed lines);
Slope at equatorward cavity edge (1.20 Rsun) = -3.0e-08+/-5.3e-09 (Bsun/degree)
Slope at equatorward cavity edge (1.26 Rsun) = -2.0e-08+/-4.7e-09 (Bsun/degree)
Slope at poleward cavity edge (1.20 Rsun) = 1.2e-08+/-5.3e-09 (Bsun/degree)
Slope at poleward cavity edge (1.26 Rsun) = 1.2e-08+/-4.7e-09 (Bsun/degree)

length lower limit = 3 days visible in white light at limb July 20; -21**; -22*** (LASCO/EIT CME (23)!);

Recurrence =East limb May 16; -18; West limb May 27; -28; -29; -31; East limb June 12; -13; West limb June 25; -26; -27; East limb July 8; -9; -10; -11; -12; -13; -14; -15; -16; West limb July 20; -21**; -22*** (LASCO/EIT CME (23)!); Visible on both limbs July 8-10, possibly also July 21-22
Evolution comments = BIG PCF system. Kinked NL straightens over a two and a half months. At least one eruption, June 6, when it is mostly still behind the limb. Appears larger (wider, higher) and darker at the limb before erupting in CME on July 23. Unfortunately, MLSO stops observing before this CME.

Neutral line orientation at the limb = -9.02 +/- 5.26 degrees from line-of-sight projected onto solar disk; 84.89 +/- 3.44 degrees from N-S
CME/dimmings association = CME July 23; prominence eruption on July 23;

Active region association = N/A

Filament/FC association = PCF-N; channel extending across disk, nearly parallel the whole way

Other comments: cavity visible in EUV

Filament - visible in white light

Necking - no neck


Cavity list (e.g. Tables 2 + 3)
Full list of cavity days observed
List of best cavity days (SET 1) observed (e.g. Table 1)
CMEs associated with cavities (e.g. Tables 7 + 8)
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