SUN COURSE - SLIDE SHOW 2

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SUN COURSE - SLIDE SHOW 3
Show 1 -- photosphere
& sunspots
Today:
SOHO
Show 2 -- corona & solar cycle
1. SOHO (Solar & Heliospheric Observatory)
Qui ckTime™ and a Sorenson Video decompr essor ar e needed to see thi s picture.
Computer animation of trip to orbit 1% of distance to Sun
New collaborative ESA/NASA mission - launched Dec 1995
--> 1st comprehensive view of Sun
SOHO Orbit
Qui ckTime™ and a Sorenson Video decompr essor ar e needed to see thi s picture.
Orbiting Sun at L1 point in phase with Earth
Observing Sun continuously for first time
Results breathtaking
MANY NEW SURPRISES --> only three
Suite 11 Instrument Packages
Solar wind - SWAN, CELIAS, CEPAC
Atmosphere:
* LASCO - Visible Light Coronagraph UVCS - Ultraviolet Coronagraph * EIT - Extreme UV telescope - global imagesCDS - Spectrum EUV -> n, T, v + raster
SUMER - Spectrum EUV -> n, T, v + raster
Interior
* MDI - Oscillations Imager + B
GOLF - Global Velocity Oscillations
* VIRGO - Irradiance Variations
E.G. from CDS
The
SUN
Last
Week
The
photo
sphere
(Big
Bear)
The
SUN
TODAY
The
photo
sphere
(SOHOMDI)
Magnetic
field
(SOHOMDI)
Chromo
sphere
(Ha Big
Bear)
Chromo
sphere
(CaK Big
Bear)
Chromo
sphere
(SOHOEIT)
Corona
at 1.3
MK
(EIT)
Corona
at 1.6
MK
(EIT)
Corona
at 2.3
MK
(EIT)
2. QNs. (i) -- ? Earth Influenced
by S Variability
Number of Sunspots Oscillates w. 11-year Cycle
SURPRISE (1976)
Realised NO sunspots in most of 17th centy
"Maunder Minimum" -- Little Ice Age
So B on Sun affects climate of Earth !!
How ??
SOHO --> Total Emission (t) 1996-2000
Emission varies
by 0.2% -passage sunspots
Increase by 0.1%
from sunspot min
to max
? Contribution
to global
warming
SURPRISE (2001)
Discovered that Global B of Sun doubled since 1900
? Effect on Global T
of Earth
Observed increase in T
(blue)
Best estimate of increase
caused by Sun (yellow)
Only 1/3 global
warming (1970 to
2000) caused by Sun
? Mechanism couple Sun/climate
QN. (ii) -- ? Structure of Solar Interior
Guitar string can oscillate in different normal modes
Sun too
Recently discovered several million
SOHO
Measures velocity
of Sun's surface at
million pts/min
Deduces frequencies:
Deduced T(r) -agrees with model to
< 1%
Deduce Internal Rotation
Observe:
* Faster at equator -Expect:
* const. on cylinders
* B generated
throughout conv. zone
Surprise:
-- const on radial lines
-- intense shear layer
? site dynamo
QN(iii)-? How Do Mass Ejections Occur
SOHO Coronagraph -- Artificial eclipse
Discovered huge ejections of plasma
Can reach Earth - communications / satellites
Comet + Comet
Next
TODAY SOHO
LASCO
Coronagraph
Further
Out
(LASCO
C3)
? Effect on the Earth -- Space Weather
Other Consequences
Damage to satellites, astronauts
Disruption to radio/phone communications, power grids
Cause of
Eruption
Magnetic
Catastrophe
(2D)
3D
Model
Magnetic
Catastro
phe

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