Download - 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008
![Page 1: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/1.jpg)
1
Physical Processes in
Solar and Stellar Flares
Eric Hilton
General Exam
March 17th, 2008
![Page 2: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/2.jpg)
2
Outline
• Overview and Flare Observations
• Physical Processes on the Sun– Standard Two-ribbon Model – Magnetic Reconnection– Particle Acceleration
• Stellar Comparison
• Summary
![Page 3: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/3.jpg)
3
The Sun
![Page 4: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/4.jpg)
Magnetic loopsTRACE image
Footprints
~ 109 cm
![Page 5: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/5.jpg)
5
Flare basics
• Flares are the sudden release of energy, leading to increased emission in most wavelength regimes lasting for minutes to hours.
![Page 6: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/6.jpg)
6
Light curves
QuickTime™ and a decompressor
are needed to see this picture.
Kane et al., 1985
Time
White light
Radio
X-rays
![Page 7: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/7.jpg)
7
QuickTime™ and a decompressor
are needed to see this picture.
Moving Footprints
![Page 8: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/8.jpg)
8
QuickTime™ and a decompressor
are needed to see this picture.
Moore et. al, 2001
Sigmoid model
![Page 9: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/9.jpg)
9
Data of Sigmoid
QuickTime™ and a decompressor
are needed to see this picture.
Moore et. al, 2001
RHESSI data
attribute
![Page 10: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/10.jpg)
10
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
![Page 11: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/11.jpg)
11
![Page 12: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/12.jpg)
12
Where does the energy come from?
A typical Solar flare emits about 1032 ergs total.
The typical size is
L ~ 3x109 cm, H ~ 2x109 cm, leading to V ~ 2x1028 cm3
Thermal energy?
In the chromosphere, the column density, col is ~0.01 g/cm2 and T~ 1x104 K.
In the corona, it’s 3x10-6 g/cm2, 3x106 K
Eth ≈ 3 colkTL2/mH ≈ 2x1029 ergs for chromosphere
≈ 2x1028 ergs for corona.
Not cutting it.
![Page 13: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/13.jpg)
13
Nuclear power?
QuickTime™ and a decompressor
are needed to see this picture.
The corona doesn’t have the temperature or density, unless…
![Page 14: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/14.jpg)
14
No, magnetic energy
EB = VB2/(2o) so , for B = 300-1000 G, you’re at 1x1032-33 erg.
Now, how is the energy released quickly enough?
t ~ L2 o ~ 5x1011 seconds for diffusion, way too long
So, do it quickly in a current sheet
![Page 15: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/15.jpg)
15
Outline
• Overview and Flare Observations
• Physical Processes on the Sun– Standard Two-ribbon Model– Magnetic Reconnection– Particle Acceleration
• Stellar Comparison
• Summary
![Page 16: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/16.jpg)
16
“Magnetic event”(reconnection)
Two-Ribbon Flare Model
Martins & Kuin, 1990
![Page 17: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/17.jpg)
17
Flow and impaction of
current sheet
Two-Ribbon Flare Model
Gyrosynchrotron radio emission
Brehmsstrahlung hard X-ray& optical emission
Martins & Kuin, 1990
![Page 18: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/18.jpg)
18
Chromospheric
evaporation &
condensation
Two-Ribbon Flare Model
Blue-shifted UV (≈100s km/s)
Red-shifted optical (≈10s km/s)
Gyrosynchrotron radio emission
Martins & Kuin, 1990
![Page 19: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/19.jpg)
19
Two-Ribbon Flare ModelSoft X-ray
Optical
Corona become optically
thick
Martins & Kuin, 1990
![Page 20: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/20.jpg)
20
Post flare emission(quiescent)
Two-Ribbon Flare Model
Gyrosynchrotron radio emission
Optical
Martins & Kuin, 1990
![Page 21: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/21.jpg)
21
This model explains…
• the relationship to CMEs
• the Neupert effect
• Sunquakes
• Radio observations
![Page 22: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/22.jpg)
22
Outline
• Overview and Flare Observations
• Physical Processes on the Sun– Standard Two-ribbon Model– Magnetic Reconnection– Particle Acceleration
• Stellar Comparison
• Summary
![Page 23: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/23.jpg)
23
Magnetic Reconnection
Sweet-Parker
(1958,1957)
QuickTime™ and a decompressor
are needed to see this picture.
B-field lines
vinflow
• Material flows in
• v x B gives current into the page
• called a ‘current sheet’ or ‘neutral sheet’
•current dissipation heats the plasma
![Page 24: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/24.jpg)
24
Magnetic Reconnection
Sweet-Parker
(1958,1957)
QuickTime™ and a decompressor
are needed to see this picture.
B-field lines
vinflow
vout
Pressure is higher in the reconnection region, so flows out the ends
![Page 25: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/25.jpg)
25
Petschek mechanism
QuickTime™ and a decompressor
are needed to see this picture.
Priest & Forbes, 2002
![Page 26: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/26.jpg)
26
Reconnection Inflow
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
Narukage & Shibata, 2006
![Page 27: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/27.jpg)
27
Outline
• Overview and Flare Observations
• Physical Processes on the Sun– Standard Two-ribbon Model– Magnetic Reconnection– Particle Acceleration
• Stellar Comparison
• Summary
![Page 28: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/28.jpg)
28
Particle acceleration
1. DC from E-fields ~ 103 Vm-1 during reconnection
2. MHD shocks - accelerate more particles more slowly - can explain the main phase
3. Highly turbulent environment may give rise to stochastic acceleration - ie fast-mode Alfven-waves.
![Page 29: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/29.jpg)
29
Ion beam• 2.223 MeV is a neutron capture line - ions collide with atmosphere, producing fast neutrons.
• These neutrons thermalize for ~100 sec before being captured by Hydrogen.
• Hydrogen is turned into Deuterium, releasing a -ray
• Time profiles (with 100 sec delay) suggest beams happen at same time.
![Page 30: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/30.jpg)
30
Displaced ion and electron beams
Hurford et al.,20062003, Oct 28th flare
4th with measured gamma rays - all showing displacement between - and hard X-rays. This is first to show both footprints
![Page 31: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/31.jpg)
31
Ion and electron beam displacement•Possible displacement caused by drift of electrons and ions with different sign of charge. This effect is 2 orders of magnitude too small.
• Currently, it’s not known why there is displacement.
![Page 32: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/32.jpg)
32
Gamma-ray movie
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
Soft X-Rays Hard X-Rays Gamma Rays
![Page 33: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/33.jpg)
33
New model for particle acceleration
Fletcher & Hudson, 2008 (RHESSI Nugget #68, Feb 4th, 2008)
![Page 34: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/34.jpg)
34
Outline
• Overview and Flare Observations
• Physical Processes on the Sun– Standard Two-ribbon Model– Magnetic Reconnection– Particle Acceleration
• Stellar Comparison
• Summary
![Page 35: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/35.jpg)
35
Stellar comparison
• When we look at a star, we lose all spatial resolution, lots of photons, and continuous monitoring.
• We can’t observe hard X-rays, and only observe limited soft X-rays
• We gain new regimes of temperature, magnetic field generation and configuration, plasma density, etc.
• We can adopt the Solar analogy, but is it valid? What observations can we make?
![Page 36: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/36.jpg)
36
Osten et al., 2005
Stellar Flares
![Page 37: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/37.jpg)
37
QuickTime™ and a decompressor
are needed to see this picture.
Big stellar flares
QuickTime™ and a decompressor
are needed to see this picture.
Hawley & Pettersen, 1991
![Page 38: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/38.jpg)
38
Flare - quietData courtesy of Marcel Agüeros
![Page 39: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/39.jpg)
39
X-ray/microwave ratio
QuickTime™ and a decompressor
are needed to see this picture.
Benz & Gudel, 1994
![Page 40: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/40.jpg)
40
The Sun is not a Flare Star!
• Although some parts of the analogy clearly hold, we would not see flares on the Sun if it were further away.
• Are the flares we see fundamentally different?
• We are biased to detecting only the largest flares, so must be cautious about extrapolating to rates of smaller flares.
![Page 41: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/41.jpg)
41
Solar vs. StellarAschwanden, 2007
![Page 42: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/42.jpg)
42
Mullan et al.,2006
Magnetic loop lengths
V-I
L/R
![Page 43: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/43.jpg)
43
EUVE Flare rates
Audard et al., 2000
![Page 44: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/44.jpg)
44
My Thesis
• I will make hundreds of hours of new observations of M dwarfs to determine flare rates
• I am creating model galaxy simulations to predict flare rates on a Galactic scale that includes spectral type and activity level. We can ‘observe’ this model to predict what LSST will see.
![Page 45: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/45.jpg)
45
Summary of Solar Flares
• Magnetic loops become entangled by motions of the footprints, storing magnetic energy
• This energy is released through rapid magnetic reconnection that accelerates particles.
• Flares emit in all wavelength regimes.• The general theory is well-established, but
the details continue to be very complex.
![Page 46: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/46.jpg)
46
The Sun, in closing
“Coronal dynamics remains an active research area. Details of the eruption process including how magnetic energy is stored, how eruptions onset, and how the stored energy is converted to other forms are still open questions.”
- Cassak, Mullan, & Shaypublished March 3rd, 2008
![Page 47: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/47.jpg)
47
Summary of Stellar Flares
• Many aspects of the Solar model seem to be true on stars as well.
• Observations have revealed inconsistencies that have not yet been resolved.
• Flares are the coolest!
![Page 48: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/48.jpg)
48
Thanks
• Thanks to my committee, esp. Mihalis for coming all the way from Ireland on St. Patrick’s Day.
• Thanks to my fellow grad students for feedback on my practice talk.
![Page 49: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/49.jpg)
49
The End
![Page 50: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/50.jpg)
50
Radio Flares Osten et al.,2005
![Page 51: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/51.jpg)
51
X-ray flares
![Page 52: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/52.jpg)
52
Stats of RHESSI flares
QuickTime™ and a decompressor
are needed to see this picture.
Su, Gan, & Li, 2006
![Page 53: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/53.jpg)
53
Stats con’t
QuickTime™ and a decompressor
are needed to see this picture.
Su, Gan, & Li, 2006
![Page 54: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/54.jpg)
54
Stats con’td
QuickTime™ and a decompressor
are needed to see this picture.
Su, Gan, & Li, 2006
![Page 55: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/55.jpg)
55
Stats con’td
QuickTime™ and a decompressor
are needed to see this picture.
Su, Gan, & Li, 2006
![Page 56: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/56.jpg)
56
Statistical motivation for Avalanche
QuickTime™ and a decompressor
are needed to see this picture.
Charbonneau et al., 2001
![Page 57: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/57.jpg)
57
Downward motion of centroid
Sui, Homan, & Dennis, 2004
6-12keV *0.5
25-50keV
![Page 58: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/58.jpg)
58
Disproving nano-flare heating
Aschwanden, 2008
![Page 59: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/59.jpg)
59
Reconnection & X-ray flux
Jing et al., 2005
![Page 60: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/60.jpg)
60
Correlations
Jing et al., 2005
![Page 61: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/61.jpg)
61
CMEs
Jing et al., 2005
![Page 62: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/62.jpg)
62
Neupert Effect
Veronig et al., 2005
![Page 63: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/63.jpg)
63
Gamma-ray spectroscopy
Smith et al., 2003
![Page 64: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/64.jpg)
64
Movie-time
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
![Page 65: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/65.jpg)
65
![Page 66: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/66.jpg)
66
Loop lengths in active stars
Mullan et al.,2006
![Page 67: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/67.jpg)
67
Avalanche
Such models, although a priori far removed from the physics of magnetic reconnection and magnetohydrodynamical evolution of coronal structures, nonetheless reproduce quite well the observed statistical distribution of flare characteristics. - Belanger, Vincent, & Charbonneau, 2007
![Page 68: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/68.jpg)
68
The model
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
![Page 69: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/69.jpg)
69
Model results
QuickTime™ and a decompressor
are needed to see this picture.
Charbonneau et al., 2001
![Page 70: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/70.jpg)
70
Model results
QuickTime™ and a decompressor
are needed to see this picture.
Charbonneau et al., 2001
![Page 71: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/71.jpg)
71
SOC-Cascades of Loops
QuickTime™ and a decompressor
are needed to see this picture.
Hughes, et al.,2003
![Page 72: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/72.jpg)
72
Cassak et. al, 2008
![Page 73: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/73.jpg)
73
Peak values during the flares
QuickTime™ and a decompressor
are needed to see this picture.
Benz & Gudel, 1994
![Page 74: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/74.jpg)
74
Sunquakes
QuickTime™ and aCinepak decompressor
are needed to see this picture.
![Page 75: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/75.jpg)
75
More complicated reconnection
• Petschek is just a special case of almost-uniform reconnection
• There are also non-uniform models with separatrix jets.
• In some cases, the sheet tears, and enters the regime of impulsive bursty reconnection
• The 3D models are very complicated 3D MHD.
![Page 76: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/76.jpg)
76
More sigmoid
QuickTime™ and a decompressor
are needed to see this picture.
Moore et. al, 2001
![Page 77: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/77.jpg)
77
Types of Magnetic Emission
Flaring: strong, impulsive emission that decays rapidly (minutes to hours), both line and continuum flux may be detected (L ≈ 10-3 - 102 Lbol)
Quiescent: steady emission that persists over long periods, typically line flux only in optical (L ≈ 10-6 - 10-3 Lbol)
Liebert et al. (1999)
![Page 78: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/78.jpg)
78
Twisted field lines
QuickTime™ and a decompressor
are needed to see this picture.
Priest & Forbes, 2002
![Page 79: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/79.jpg)
79
Solar to stellar - scaling laws
Aschwanden, 2007
![Page 80: 2 Physical Processes in Solar and Stellar Flares Eric Hilton General Exam March 17th, 2008](https://reader034.vdocuments.mx/reader034/viewer/2022052603/56649cb15503460f949763a7/html5/thumbnails/80.jpg)
80
Veronig et al., 2005