Upload
katy-ironside
View
224
Download
1
Tags:
Embed Size (px)
Citation preview
Phillip ChamberlinUniversity of
ColoradoLaboratory for Atmospheric and Space Physics
(LASP)[email protected]
(303)492-9318
QuickTime™ and aYUV420 codec decompressorare needed to see this picture.
June 12, 2007
Chamberlin - Solar Flares - REU 2007
2
Outline- Solar Atmosphere- Flux Tubes- Two Ribbon Flare
- Cartoons- Movies
- Irradiance Measurements of Flares- VUV- White Light- TSI
June 12, 2007
Chamberlin - Solar Flares - REU 2007
3
XUV, EUV, and FUV Solar Spectrum
Transition Region
From Lean (1997)
June 12, 2007
Chamberlin - Solar Flares - REU 2007
4
Solar Images - Oct. 28, 2003
PhotosphereTransition Region
Chromosphere
H-Alpha Coron
a
QuickTime™ and aYUV420 codec decompressorare needed to see this picture.
(Images courtesy of Big Bear Solar Observatory and SOHO EIT)
June 12, 2007
Chamberlin - Solar Flares - REU 2007
5
Flux Tubes
(Schrijver and Zwaan, 2000)
June 12, 2007
Chamberlin - Solar Flares - REU 2007
6
Flux Tubes
(Schrijver and Zwaan, 2000)
Absence of B-field within convection cells due to B-field line reconnection
B-field lines concentrated in strands between convection cells to form Flux Tubes
Initial rotating convection zone with weak vertical B-field lines
June 12, 2007
Chamberlin - Solar Flares - REU 2007
7
Emerging Flux
Solar Atmosphere
Convection Zone
Active Regions
(Schrijver and Zwaan, 2000)
Balance between hydrostatic pressure and magnetic pressure causes the flux tubes to be less dense due to their stronger magnetic pressure buoyant flux tubes
June 12, 2007
Chamberlin - Solar Flares - REU 2007
8
Emerging Flux (Title, 2004)
QuickTime™ and aVideo decompressorare needed to see this picture.
June 12, 2007
Chamberlin - Solar Flares - REU 2007
9
Phases of Solar Flares
Radio (100-500 MHz) Microwave Radio (~3000 MHz)
H-alpha (656.2 nm)
Broadband EUV (1 - 103 nm)
Soft X-rays (< 10 keV)X-rays (10-30 keV)
Hard X-rays (> 30 keV)
Precursor
Impulsive Phase
Main Phase
(Adapted from Schrijver and Zwaan, 2000)
Note: Soft X-rays: 0.1-10 nm,
Hard X-rays: 0.001-0.1 nm
June 12, 2007
Chamberlin - Solar Flares - REU 2007
10
Two-Ribbon Flare
(Priest, 1981)
Triggered by Emerging Flux?
Eruption when some critical limit is reached
Continued thermal heating and formation of post-flare loops
“Stretching” of field lines
June 12, 2007
Chamberlin - Solar Flares - REU 2007
11
Two-Ribbon Reconnection
Reconnection after instability accelerates material down loop. Observed Hard X-ray (and EUV?) enhancements at loop top.No enhanced emissions during the impulsive phase in the corona due to its low density.
[Ashwanden,2004]
Thick-target model produces Bremsstrahlung radiation in the transition region and chromosphere due to their much higher densities - Impulsive Phase!Energy deposited during the impulsive phase heats the plasma up and rises (chromospheric evaporation) to fill flux tube - Gradual Phase!
June 12, 2007
Chamberlin - Solar Flares - REU 2007
12
Two-Ribbon Flare
Post-Flare Loops
Impulsive Phases for Each Loop
(Somov, 1992)
June 12, 2007
Chamberlin - Solar Flares - REU 2007
13
X28 Flare, Nov 4, 2003
June 12, 2007
Chamberlin - Solar Flares - REU 2007
14
Hinode SOT Observes Flare
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
June 12, 2007
Chamberlin - Solar Flares - REU 2007
15
SOHO (UV) and SORCE XPS (XUV) Observations
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
June 12, 2007
Chamberlin - Solar Flares - REU 2007
16
Phases of Solar Flares
Radio (100-500 MHz) Microwave Radio (~3000 MHz)
H-alpha (656.2 nm)
Broadband EUV (1 - 103 nm)
Soft X-rays (< 10 keV)X-rays (10-30 keV)
Hard X-rays (> 30 keV)
Precursor
Impulsive Phase
Main Phase
(Adapted from Schrijver and Zwaan, 2000)
Note: Soft X-rays: 0.1-10 nm,
Hard X-rays: 0.001-0.1 nm
June 12, 2007
Chamberlin - Solar Flares - REU 2007
17
Flare/Pre-Flare Irradiance Ratio
EUV irradiance increased by a factor of 2 during the gradual phase
Transition region emissions increased by up to a factor of 10 during the impulsive phase
Flare Variations were as large or larger than the solar cycle variations for the Oct 28, 2003 flare
June 12, 2007
Chamberlin - Solar Flares - REU 2007
18
X-Ray Classification
Due to the large, order-of-magnitude increases in the soft X-rays makes for an ideal and sensitive classifications of the magnitude of flares
June 12, 2007
Chamberlin - Solar Flares - REU 2007
19
White Light Flare• “Carrington Flare” September 1, 1859– Carrington (M.N.R.A.S, 20, 13, 1860)
• One of the largest flares believed to have occurred since then
• Two-Ribbon flare
June 12, 2007
Chamberlin - Solar Flares - REU 2007
20
White Light vs UV (170 nm) Flare
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
White Light
170 nmTRACE
From Hudson et al., AGU/SPD 2005: http://sprg.ssl.berkeley.edu:80/~hhudson/presentations/spd_wl.050527/
June 12, 2007
Chamberlin - Solar Flares - REU 2007
21
X17 flare observed in TSIFirst detection of flare
in TSI record (G. Kopp, 2003)
Figures from G. Kopp, arranged by T. Woods
June 12, 2007
Chamberlin - Solar Flares - REU 2007
22
Conclusions
• Multiple images and spectral measurements are key to understanding energetic of flares
• New measurements (Hinode, EVE, AIA, etc.) will lead to a much greater understanding of these processes
• Biggest mystery still is the ‘trigger’
• Another topic to that is not fully understood is the relationship of CMEs and Flares
June 12, 2007
Chamberlin - Solar Flares - REU 2007
23
Extra Slides
June 12, 2007
Chamberlin - Solar Flares - REU 2007
24
Simple Loop FlareExisting Flux Loop that Brightens
-Most Common Type
-Are these an actual separate type of flare?
-Only Enhanced Internal Motions (Priest,
1981)
PHOTOSPHERE
CHROMOSPHERE
CORONA TRANSITION REGION
June 12, 2007
Chamberlin - Solar Flares - REU 2007
25
Flares drive waves in the photosphere
QuickTime™ and aCinepak decompressor
are needed to see this picture.
June 12, 2007
Chamberlin - Solar Flares - REU 2007
26
Hinode SOT Movie #2
QuickTime™ and aSorenson Video 3 decompressorare needed to see this picture.
June 12, 2007
Chamberlin - Solar Flares - REU 2007
27
VUV Irradiance Increases Dominate Flare Variations
• VUV irradiance (0.1-200 nm) accounts for only 0.007% of quite Sun Total Solar Irradiance (TSI)
• VUV irradiance accounts for 30-70% of the increase in the TSI during a flare [Woods et al., 2006]
June 12, 2007
Chamberlin - Solar Flares - REU 2007
28
Flares Cause Sudden Atmospheric Changes
Sudden increase in the dayside density at low latitude regions due to the X17 solar flare on October 28, 2003
(E. Sutton, 2005)
• Increased neutral particle density in low latitude regions on the dayside.
• Sudden Ionospheric Disturbances (SIDs) lead to Single Frequency Deviations (SFDs).
• Cause radio communication blackouts
• Cause increased error in GPS accuracy
GRACE daytime density (490 km)
Latitude (Deg)
2003 Day of Year