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Transcript
Solar and Heliospheric Physics
CSI 769 / ASTR 769
Spring 2008
Jie Zhang
What Physics?
•Plasma Physics
•MHD (Magnetohydrodynamics) Physics
•Magnetism
•Magnetic Reconnection
•Particle Acceleration
The Cosmological Context
We are located in the
middle of the
Milky Way Galaxy
28,000 light years
from the center
One of 200 billion
stars in our Galaxy
The Sun: an Ordinary Star
•An ordinary main
sequence star
•5 billion years old
•5 billion years
more to go
Local Interstellar space
Solar wind
creates a big
teardropshaped
heliosphere
around the
solar system,
by interacting
with the
interstellar
wind
Local Interplanetary Space
The Earth
3rd planet from
the Sun
1 AU = 150
million km
Travel time:
By light -8 minutes
By Solar Wind- ~ 100 hrs
What Practical Usage?
"Space weather describes the conditions in space
that affect Earth and its technological systems.
Our space weather is a consequence of the
behavior of the sun, the nature of Earth's
magnetic field, and our location in the solar
system”
----National Academy of Science, 1997
Space Weather: the Process
It starts
from an
eruption
from the
Sun.
Prediction
depends on
how it
propagates
Space Weather: effects
Aurora; Geomagnetic Storm
From Space
Space Weather: effects
An adverse effect
Power failure due to
March 1989 storm
Damaged transformer
Space Weather: effects
On Human Space Exploration
On crew and
passengers of
polar-route
airplanes
Space Weather: effects
On Satellite Operation
Space Weather: effects
On Communication and Navigation
Space Weather: the Systems
The Source of the Energy?
Planet
Magnetic energy through magnetic field
generated by solar dynamo, which has 11-year
solar cycle
Solar Cycle
Storage of Energy?
Planet
Energy stored and released in magnetic field
Release of Energy and the
driver?
Planet
Coronal mass ejections
Heliosphere: solar wind
Planet
Spiral solar wind magnetic field: radial motion
of solar wind combined with Sun’s rotation
Sprinkler
Analogy
Magnetosphere
Planet
A cometshaped
region
around the
Earth
Magnetosphere
Planet
Electric
Currents in
Magnetosphere
Magnetosphere
Planet
Energetic
particles in
Van Allen
radiation
belt
Ionosphere
Planet
Density fluctuation affects radio wave
reflection and transmission
Neutral Upper Atmosphere
Planet
It is coupled with ionosphere
Re-focus on Physics
•Energy Storage: magnetism
•Energy Release: magnetic reconnection
•Energy Transportation
The End