The Stormy Sun

1
The Stormy Sun
Solar Activity and its Impact on Earth
2
(No Transcript)
3

• The Sun produces
• Radiation
• Magnetic field
• High energy
• particles

Image UCAR Windows to the Universe
Image SLAC website
4
A solar eclipse in 1991
Solar Variation
A solar eclipse in 1996
Images High Altitude Observatory
5
Image NASA/TRACE
6
The number of sunspots increases and
decreases, approximately every 11 years This
is known as the Solar Cycle
Magnetic Field on Suns Surface
Million-degree active regions
7
Image Lockheed Martin/Yohkoh SXT
8
The Sun is also changing on a timescale of days
MovieESA/NASA SoHO EIT
Approximately 10 days of solar rotation
9
Image NASA/Lockheed Martin/TRACE
Magnetic arches, or loops, extending from the
surface of the sun, often produce solar flares
10
Movie ESA/NASA SoHO EIT
11
Solar Explosions! (Coronal Mass Ejections)
Image ESA/NASA SoHO EIT
12
Coronal Mass Ejections seen by the LASCO
telescope on SoHO
15 of distance to Earth
Movie ESA/NASA SoHO LASCO
13
Image NASA/Sun-Earth Connections Program
We live inside the atmosphere of a star
Particles, radiation and magnetic field from the
Sun influence our own environment.
14
The Earths Atmospheric Shield
Image NASA
15
The Earths Magnetic Shield
Image NASA/Sun-Earth Connections Program
16
Particles from the Sun, and those accelerated in
our own magnetosphere by solar storms, generate
aurorae
Images E.Ebihara
17
Image Windows to the Universe, UCAR
18
The Aurora Australis and Space Shuttle Discovery
Image NASA
19
Image L.Lanzerotti, Lucent Bell Labs
20
There are many thousands of satellites in
orbit about the Earth
Orbital heights range from a few hundred to tens
of thousands of kilometers
Used for many purposes - telecommunications,
military, research...
Images Windows to the Universe, UCAR
21
Satellite problems are caused by single particle
hits in critical logic circuits, interior
charging, and loss of altitude
Image Windows to the Universe, UCAR
22

• High energy particles and increased ultra-violet
  and X-ray
• radiation during a flare heat the atmosphere
• Magnetised plasma from the CME compresses the
  magnetosphere
• and ionosphere

Increased drag causes satellites to lose
altitude eg 1989 SMM satellite 2000 ASCA
satellite
Coverage of Earth where density was more than 20
above average during a moderate magnetic storm.
Image Windows to the Universe, UCAR
23
Image L.Lanzerotti, Lucent Bell Labs
24
Solar Panels are damaged by high energy ions
from flares, which slice through and destroy the
semiconductor
In 1989, the panels on a GOES satellite lost 3
years of operating lifetime during one solar
proton event (lasting a few days)
Image Windows to the Universe, UCAR
25
Image L.Lanzerotti, Lucent Bell Labs
26
Image Windows to the Universe, UCAR/Michigan
Power
27
Transformers work on AC. So, introduce a
large magnetically- induced DC current and...
Image Windows to the Universe, UCAR
28
...10 million goes up in smoke
Step-up Transformer in Quebec power grid,
following March 89 event
Image HydroQuebec
29
Image L.Lanzerotti, Lucent Bell Labs
30
Radiation Calculation for astronauts on the way
to the moon.
Image Windows to the Universe, UCAR
31
Image Windows to the Universe, UCAR
32
Image L.Lanzerotti, Lucent Bell Labs
33
Solar Storm Effects on radio/TV/communications
signals
Waveband Common Use
Effect Long
Wave Navigation, military
ionospheric disturbances
communication lead to
signal attenuation. Medium Wave AM radio
relatively
unaffected Short Wave search
rescue, severe enhanced
ionisation
police, taxis, CB by X-rays and
particles
leads to
dramatic blackouts VHF
FM radio, TV signal quality
affected
satellite phone by ionospheric
scattering UHF
GPS, some mobile poor signal
quality and
digital TV networks especially at poles.
34
Solar activity may also have some influence on
climate
The Maunder Minimum (1645-1715)
corresponded to a period of exceptionally
cold winters throughout Europe
35
Regions of significant correlation between cloud
cover and sunspot number (Udelhofen et al. 2001)
Correlation between land temperature and solar
cycle length (Baliunas Soon, 1995)
36
A Lucky Escape? The 2 April 2001 Flare was the
most energetic flare yet recorded but we were
saved from the worst effects
Magnetic field direction
37
Whats headed our way today?