Phillip Chamberlin
University of Colorado
Laboratory for Atmospheric
and Space Physics (LASP)
Phil.Chamberlin@lasp.colorado.edu
(303)492-9318
Outline
- Solar Atmosphere
- Flux Tubes
- Two Ribbon Flare
- Cartoons
- Movies
- Irradiance Measurements of Flares
- VUV
- White Light
- TSI
June 10, 2009
Chamberlin - Solar Flares - REU 2009
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XUV, EUV, and FUV Solar Spectrum
Transition Region
From Lean (1997)
June 10, 2009
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Solar Images - Oct. 28, 2003
Chromosphere
H-Alpha
Corona
Photosphere
Transition
Region
(Images courtesy of Big Bear Solar
Observatory and SOHO EIT)
June 10, 2009
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Flux Tubes
(Schrijver and Zwaan, 2000)
June 10, 2009
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Flux Tubes
Initial rotating
convection zone
with weak
vertical B-field
lines
B-field lines
concentrated in
strands between
convection cells to
form Flux Tubes
Absence of B-field
within convection
cells due to B-field
line reconnection
(Schrijver and Zwaan, 2000)
June 10, 2009
Chamberlin - Solar Flares - REU 2009
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Emerging Flux
Solar Atmosphere
Active
Regions
Convection
Zone
Balance between
hydrostatic pressure
and magnetic
pressure causes the
flux tubes to be less
dense due to their
stronger magnetic
pressure
buoyant flux tubes
(Schrijver and Zwaan, 2000)
June 10, 2009
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Emerging Flux (Title, 2004)
June 10, 2009
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Solar Flares
June 10, 2009
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Phases of Solar Flares
Radio (100-500 MHz)
(Adapted from Schrijver and
Zwaan, 2000)
Microwave Radio
(~3000 MHz)
H-alpha (656.2 nm)
Broadband EUV (1 - 103 nm)
Soft X-rays (< 10 keV)
X-rays (10-30 keV)
Main Phase
Impulsive Phase
Precursor
Hard X-rays (> 30 keV)
Note: Soft X-rays: 0.1-10 nm,
Hard X-rays: 0.001-0.1 nm
June 10, 2009
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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.
June 10, 2009
[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!
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Jets Evidence of Small-Scale
Reconnection?
June 10, 2009
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Two-Ribbon Flare
Triggered by
Emerging
Flux?
“Stretching” of
field lines
Eruption when
some critical
limit is reached
Continued thermal
heating and
formation of postflare loops
(Priest, 1981)
June 10, 2009
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Phases of Solar Flares
Radio (100-500 MHz)
(Adapted from Schrijver and
Zwaan, 2000)
Microwave Radio
(~3000 MHz)
H-alpha (656.2 nm)
Broadband EUV (1 - 103 nm)
Soft X-rays (< 10 keV)
X-rays (10-30 keV)
Main Phase
Impulsive Phase
Precursor
Hard X-rays (> 30 keV)
Note: Soft X-rays: 0.1-10 nm,
Hard X-rays: 0.001-0.1 nm
June 10, 2009
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Two-Ribbon Flare
Post-Flare Loops
June 10, 2009
Impulsive Phases
for Each Loop
Chamberlin - Solar Flares - REU 2009
(Somov, 1992)
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Flares drive waves in the
photosphere
June 10, 2009
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X28 Flare, Nov 4, 2003
June 10, 2009
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Hinode SOT Observes Flare
June 10, 2009
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SOHO (UV) and SORCE XPS
(XUV) Observations
June 10, 2009
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Phases of Solar Flares
Radio (100-500 MHz)
(Adapted from Schrijver and
Zwaan, 2000)
Microwave Radio
(~3000 MHz)
H-alpha (656.2 nm)
Broadband EUV (1 - 103 nm)
Soft X-rays (< 10 keV)
X-rays (10-30 keV)
Main Phase
Impulsive Phase
Precursor
Hard X-rays (> 30 keV)
Note: Soft X-rays: 0.1-10 nm,
Hard X-rays: 0.001-0.1 nm
June 10, 2009
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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 3070% of the increase in the TSI
during a flare [Woods et al., 2006]
June 10, 2009
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Flare/Pre-Flare Irradiance Ratio
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 10, 2009
Chamberlin - Solar Flares - REU 2009
EUV irradiance
increased by a
factor of 2
during the
gradual phase
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X-Ray Classification
Due to the large,
order-ofmagnitude
increases in the
soft X-rays makes
for an ideal and
sensitive
classifications of
the magnitude of
flares
June 10, 2009
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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 in the
past 200 years
• Two-Ribbon
flare
June 10, 2009
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Flares in
Photosphere
and
Chromosphere
Hinode SOT
Observations
June 10, 2009
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X17 flare observed in TSI
First detection of flare in TSI record
(G. Kopp, 2003)
Figures from G. Kopp, arranged by T. Woods
June 10, 2009
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Conclusions
• Multiple images and spectral measurements
are key to understanding energetic of flares
• New measurements (Hinode, Stereo, 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 10, 2009
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Extra Slides
June 10, 2009
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Simple Loop Flare
Existing Flux Loop that Brightens
TRANSITION
REGION
CORONA
CHROMOSPHERE
PHOTOSPHERE
-Most Common Type
-Only Enhanced Internal Motions
(Priest, 1981)
-Are these an actual separate type of flare?
June 10, 2009
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Hinode SOT Movie #2
June 10, 2009
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Flares Cause Sudden Atmospheric Changes
Latitude (Deg)
GRACE daytime density (490 km)
• Increased neutral particle
density in low latitude regions on
the dayside.
• Sudden Ionospheric
Disturbances (SIDs) lead to
Single Frequency Deviations
(SFDs).
2003 Day of Year (E. Sutton, 2005)
Sudden increase in the dayside
density at low latitude regions
due to the X17 solar flare on
October 28, 2003
June 10, 2009
• Cause radio communication
blackouts
• Cause increased error in GPS
accuracy
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