Space Weather:
From The Sun
To The Earth
Philip Erickson
Atmospheric Sciences Group
MIT Haystack Observatory
RET 2011 Workshop
Earth’s Upper Atmosphere (and most of the Solar System):
A Natural Plasma
• Plasma is the fourth state of matter
• The universe is filled with plasma
• Extreme ultraviolet output from the
Sun creates a plasma in Earth’s upper
atmosphere through ionization
Energy Flow From Sun To Earth
Solar Effects on Surface Temperature
Solar Effects On Upper Atmospheric Temperature, Density
Solar Phenomena
Flares
Solar Wind
Sunspots
Granulations
Helioseismology:
Solar Magnetograms
Doppler shifts of solar surface spectrum give oscillations
Accuracy of parts per million required
Acoustic, gravity, surface waves detected
Further Fourier analysis probes solar interior waves
Plasma and Magnetic Fields
Maxwell’s Laws: Charged particle
must oscillate around magnetic
fields (gyroresonance)
Plasma: state of matter with
negatively charged electrons,
positively charged ions
interacting by electromagnetic
forces and collisions
Universe is filled with plasma…
Sun – Earth System Overview
The Sun : Our Dynamic Star
A Local Source of Space Weather
Driven by Nuclear Fusion
Variable on Many Time Scales
The Solar Cycle
Magnetic Reconnection
At the Sun’s Surface
Solar surface (TRACE satellite)
Field lines are “painted”
with plasma;
Magnetohydrodynamic
twisting causes severe
distortions (and energy
storage)
Coronal Mass Ejections
Coronagraph Views of a CME
Earth’s Magnetosphere
Dipole Magnetic Field
The Earth's Magnetic Field Interacts with the Solar Wind
The Solar Wind is Deflected Around the Earth
The Earth's Magnetic Field is Distorted
There is Weather at the Ground… And In Space
Surface Weather
Space Weather
The Space Weather Environment
Travel Time =
2 - 3.5 Days
Solar Flare
Magnetopause
Solar Wind
Direction
Bow Shock
Geomagnetic Storms
Magnetospheric Response
Atmospheric Response
Auroral
Activity
28 November 2000
Nome, Alaska
John Russell
Aurora and Airglow From STS-100 Shuttle
(NRL)
Geomagnetic Storms
Atmospheric Response
The Ionosphere and Thermosphere
The atmosphere
appears very thin…
The Near Space Environment Is a Dynamic Place
Space Weather Effects
Geomagnetic Storms Disrupt Technological Systems
Radiation Hazards
Damage to Satellites
Communications Failures
GPS Navigation Problems
HF Propagation Forecasts: Affected By Space Weather
(Australian IPS)
MIT Haystack Observatory
Haystack Observatory
Millstone Hill Observatory
Firepond Optical
Facility
Lincoln Space Surveillance Complex
(+ HAX, LRIR)
Westford, MA
Millstone Hill Observatory
• 150 foot steerable antenna
• 220 foot zenith antenna
Observing the
Upper Atmosphere
Using Radar
Since 1960…
Observing the Ionosphere with Radar
Iterative fitting reproduces
the shape of the ionosphere
Range
Incoherent Scatter
Electrons reflect
the pulse….
Complex signal processing
extracts the frequency
spectrum
Time
High power pulse
Very sensitive receiver
Noise like signal received
Only ~0.0000000000000000001% of the
transmitted power is returned!
Incoherent Scatter Radars
O AMISR
Poker Flat
•O Svalbard
O Sondrestrom •O EISCAT
Resolute
Bay
•O Kharkov
O Millstone Hill
O AMISR
•
O Irkutsk
•
O MU
O Arecibo
•
•
•
O Jicamarca
Global Network of High Power Radars
Measure Physical Properties of the Space Environment
•
Electron density, electron temperature, ion temperature, plasma velocity, and more...
The Quiet Ionosphere – As
Measured By Radar
The Active Ionosphere – As
Measured By Radar
The Active Ionosphere – As
Measured By Radar
Space Weather Effects
Storms can adversely
affect GPS, pagers and
cell phones.
Millstone Hill Radar
Radio waves refract .. Just like light
Transcontinental propagation affected
“Twinkling” causes data loss
Global Positioning System:
Very Precise Navigation
By measuring
Delay (path length)
to each satellite…
N 42.61950°
E 288.50827°
Receiver has a simple ionospheric thickness model
Global Positioning System…
Affected By Space Weather!
Ionospheric density
changes - so delay
changes (locally).
Receiver doesn’t
know this…
Wrong position…
But – we can turn it around and derive
Ionospheric information! (Total Electron Content)
Case Study:
October 29, 2003
Superstorm
Coronal
Mass
Ejection
Visible US Auroras
Maryland (above);
Galway, NY (right)
Web-Accessible Space Weather Information
www.haystack.mit.edu