The Change of Magnetic Inclination Angles Associated with Flares

1
The Change of Magnetic Inclination Angles
Associated with Flares

• Yixuan Li
• April 1,2008

2
BACKGROUND

• Recent white-light observations demonstrated a
  consistent pattern of changes in sunspot
  structures part of the penumbral segments in the
  outer spot decays rapidly after flares, and
  meanwhile, the umbral cores and/or inner
  penumbral regions are enhanced.

3
Sunspot Structure Change (Liu et al. 2005)
(a) and (b) are TRACE WL images of preflare and
postflare states, respectively. (c) is the WL
difference image (the postflare image minus the
preflare image)
4

• The difference images for all the seven
  events show a very similar pattern with a bright
  (decaying) region outside and a darkening in the
  center.

5
Hinode G-band observations reveal similar changes
(Jing et al.)
The intensity in RG1 decreases by 12 within the
interval of two time bins while the intensity in
RG2 increases by 7. These changes denote the
enhancement of inner penumbra near the magnetic
PIL and the decay of the peripheral penumbra,
respectively.
Top row Hinode G-band images and their
difference image (right). Bottom panel
Normalized time variation of the total G-band
intensities in area RG1 and RG2 The dotted
vertical curve indicates the peak time of the
flare non-thermal emission.
6
Reconnection Picture (Liu et al. 2005)

• The two spots become strongly connected after the
  flare, leading the penumbral fields to change
  from highly inclined in the preflare state to a
  more vertical configuration after the flare. This
  accounts for the penumbral decay.
• The umbra becomes darker as a result of an
  enhanced longitudinal magnetic field. The strong
  connection between the two spots also leads to a
  substantial increase in the transverse field in
  the central d spot region, which can explain the
  darkening of the inner penumbra.
• The gray and black lines stand for penumbral and
  umbral fields, respectively.

7
Magnetic Inclination Angle
8
Hinode Spectropolarimeter (SP) magnetogram of AR
10930

• the X3.4 Flare on December 13 2006

9
G-band Image
Difference image
Decay Regions
10
Angle Distribution for the Penumbral Decay Regions
2006-12-12
2006-12-13
11
Angle Distribution for the Inner Penumbral Region
2006-12-12
2006-12-13
12

• the Hinode Spectropolarimeter (SP) have taken
  several strong flares, including three X-class
  flares
• X6.5 on December 6, 2006
• X3.4 on December 13 , 2006
• X1.5 on December 14 , 2006
• Solar atmospheric condition measurement changes
  associated with flares in both peripheral and
  inner penumbral regions
• Temperature
• Density

13
Thank you !