1. Filament/Prominence Eruption Corona Mass Ejection (CME)
CSI /PHYS Solar Atmosphere Fall 2004
Lecture Nov. 17, 2004
Filament/Prominence Eruption
Corona Mass Ejection (CME)

2. Filament/Prominence
Meudon
(France) Hα

3. Filament/Prominence
BBSO Hα

4. Filament/Prominence
Filament/Prominence: dense clouds of chromospheric-temperature material suspended in the corona
The filament material is either from cooling of coronal plasma or direct injection of chromospheric material
A filament can remain in a quiet or quiescent state for days or weeks
A filament can erupt and rise of the Sun over the course of a few minutes or hours

5. Filament in different regions
Active Region Filament
in active region
small in size
shortly lived in time (e.g., day)
Quiescent Filament
in quiet Sun region
long in size
relatively long lived (e.g., week)
Polar Crown Filament
close to polar coronal hole region
very long, e.g., circling the whole Sun at high latitude
very long lived (e.g., month)

6. Filament in different regions (cont’d)
Exp., Polar Crown Filament

7. Filament Configuration
BBSO Hα
Mt. Wilson Magnetogram

8. Filament Configuration
A filament always sits along the magnetic inversion line (magnetic neutral line) that separates regions of different magnetic polarity
A filament is supported by coronal magnetic field in a supporting configuration
Magnetic dip at the top of loop arcade (2-D)
Magnetic flux rope (3-D)
Helical or twisted magnetic structure is seen within filament

9. Filament Configuration
One of filament models: filament is supported by twisted magnetic flux rope

10. Filament Eruption

11. Filament Eruption BBSO Hα on 2003/08/05 BBSO Hα on 2004/03/24

12. Filament Eruption TRACE 195 Å, 1999/10/20
Filament eruption and loop arcade
TRACE 195 Å, 2002/05/27
A failed filament eruption
TRACE 195 Å, 1998/07/27
Filament internal motion

13. Filament Eruption Model
One model
by Martens & Kuin
A unified model of
Filament and
Flare

14. Filament Channel
A filament channel refers to the envisioned magnetic structure surrounding a filament. It may be larger than the filament itself.

15. CME (Coronal Mass Ejection)
A CME is a large scale coronal structure of plasma (and associated magnetic field) that is being ejected from the Sun, as seen by a coronagraph

16. Coronagraph Coronagraph
A telescope equipped with an occulting disk that blocks out light from the disk of the Sun, in order to observe faint light from the corona
A coronagraph makes artificial solar eclipse
CMEs are observed by coronagraphs
The earliest CME observation was made in early 1970s

17. White light seen in Corona
Textbook P
K (continuum) corona, caused by scattering of photospheric light of rapidly-moving coronal electrion (so called Thomson scattering); the major component of white-light corona
F (Fraunhofer corona), caused by scattering of photospheric light off dust in interplanetary space between the orbits of Mercury and Earth
E (Emission corona), caused by emission of radiation by highly-ionized species in the actual corona, so called forbidden emission lines, e.g., at 5302 Å from Fe XIV (coronal green line)

18. White light from Corona (cont’d)
K corona: continuum (what a solar physicist wants)
F corona: continuum plus absorption (do not want)
E corona: emission lines (textbook P. 139, Fig. 5.9)

19. White light from Corona (cont’d)
K corona brightness is less than 10-5 that of disk
The instrument design is to reduce scattering of light (Textbook P.5, Figure 1.3)

20. LASCO Coronagraphs
C1: 1.1 – 3.0 Rs (E corona) (1996 to 1998, then died)
C2: 2.0 – 6.0 Rs (white light) (1996 up to today)
C3: 4.0 – 30.0 Rs (white light) (1996 up to today)
C C C3
LASCO uses a set of three overlapping coronagraphs to maximum the total effective field of view. A single coronagraph’s field of view is limited by the instrumental dynamic range.

21. Several streamers in a typical coronagraph image

22. Streamer (cont’d)
A streamer is a stable large-scale structure in the white-light corona.
It has an appearance of extending away from the Sun along the radial direction
It is often associated with active regions and filaments/filament channels underneath.
It overlies the magnetic inversion line in the solar photospheric magnetic fields.
When a CME occurs underneath a streamer, the associated streamer will be blown away
When a CME occurs nearby a streamer, the streamer may be disturbed, but not necessarily disrupted.