Transcript BRIEFING TITLE - ALL CAPS 30 Jan 01

Space Weather: Overview and Beginnings
10 September 2011
William J. Burke
Air Force Research Laboratory/Space Vehicles Directorate
Boston College Institute for Scientific Research
CRESS
C/NOFS
DMSP
Space Weather
Overview
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Like severe terrestrial weather the space variety comes and goes
Solar sources of space climatology and weather:
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Extreme ultraviolet radiation maintains & disrupts the ionosphere
Solar wind and interplanetary magnetic field couple to Earth’s magnetic field
Energy storage and transport in the magnetosphere
Geomagnetic storms and Substorms
Space weather impacts from an Air Force perspective
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Google
Satellite and debris lost in space during magnetic storms
Ionospheric irregularities disrupt communications and navigation
Radiation damage to spacecraft components
Actual
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Predicted
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Near-Earth space is the environment in which the AF conducts
expensive operations to advance both national security and scientific
understanding about the Earth, our star and the cosmos.
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Space Weather
Course Overview
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Lecture 1:
Overview and Beginnings
Lecture 2:
Basic Physics (painlessly administered)
Lecture 3:
The Main Players
Lecture 4:
Solar Wind Interactions with the Earth’s Magnetic Field
Lecture 5:
Magnetosphere – Ionosphere Interactions
Lecture 6:
The Aurorae
Lecture 7:
Solar Induced Disruptions
Lecture 8:
Magnetic Storms and Substorms
Lecture 9
The Satellite Drag Problem
Lecture 10:
Verbindung (to help make up for your rash decision not to take
Wollen Sie Deutch Sprechen?)
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Space Weather
Historical Roots
Aurorae and Geomagnetic Disturbances
Early Auroral Reports
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Aristotle: Meterorologia (ca 340 BCE) 
Galileo (1610) sunspots, (1619) Aurora borealis
Capt. James Cook: (1770) Aurora australis from Endeavor
Herman Fritz: (1881) Aurorae occur most commonly ~23°
from magnetic poles
Early Geomagnetic Disturbance Reports
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William Gilbert: (1600) de Magnete
Edmund Halley: (1716) magnetic disturbances connected to aurora displays.
Anders Celsius & Olaf Hiorter: (1741) Magnetic needle experiments
Carl Friedrich Gauss: (1834) Göttingen Magnetic Union,
(1839) Algemeine Theorie des Erdmagnetismus
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Space Weather
Historical Roots
• The remainder of this discussion
concerns the seminal contributions
of two Norwegians to present understanding auroral electrodynamics
Kristian Birkeland (1867 – 1917)
Prof. of Physics, Royal Frederiks U. of Kristiania
Carl Størmer (1874 – 1957)
Prof. of Mathematics, Royal Frederiks U. of Kristiania
Royal Frederiks University of Kristiania
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Founded: 1811
Astrophysical Observatory: 1832
Domus Media: 1851
Blindern Campus: 1934
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Space Weather
Historical Roots
Kristian Olaf Bernhard Birkeland
• 1867: born in Kristiania
• 1880 - 1890: High school and university education
• 1893 - 1895: Postgraduate Research in France & Germany
- published 1st generalized solution of Maxwell equations
- characterized electric sparks (telegraphic applications)
- began cathode ray experiments (Röntgenstrahlen)
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1897: elected member of The Norwegian Academy
1898: appointed Professor of Physics (by King Oscar II of Sweden)
1917: died in Tokyo
88 scientific papers (more than 50 in Comptes Rendus)
3 books describing his arctic expeditions
60 patents (electromagnetic cannon/artificial fertilizer)
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Space Weather
Historical Roots
Birkeland’s Terrella Simulations:
– Concept:
– Experimental Results:
• Cathode rays fired at a
magnetized sphere
• Light emissions surround
magnetic pole like aurorae
– Birkeland’s Interpretation:
Energetic electrons (cathode rays ) from
the Sun are “sucked” into Earth’s magnetic
field and reach the upper atmosphere
where they excite optical emissions.
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Does interpretation
make sense?
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Space Weather
Historical Roots
Norwegian Polar Expeditions
• 1897 Campaign to Kåfjord
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Total disaster in surprise early autumn blizzard,
T => -25° C; student severely injured
• 1899-1900 Campaign to Kåfjord
– Constructed 2 auroral observatories at tops of Mts. Haldde and Talvik,
separated by 2.7 km but connected via telephone line
– Measured magnetic perturbations associated with overhead aurora
– Separation too small to estimate heights of aurorae by parallax
– Student Elisar Boye killed in an avalanche
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Space Weather
Historical Roots
Norwegian Polar Expeditions
• 1902 – 1903 Campaign: 4 Stations:
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Supplies, sled dogs and coal
Kåfjord, Norway
Dyrafjord, Iceland
Axeløen, Svalbard
Matotchkin, Novaya Zemlya
• All stations equipped with:
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Inter-station separation
of about 1000 km
Magnetometers and calibration sensors
Electrometers to measure atmospheric conductivity and Earth currents
Meteorological sensors to measure P, T and V
All personnel had to have experienced wintering over in the Arctic
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Space Weather
Historical Roots
Norwegian Polar Expeditions
• 1902 – 1903 Campaign Results:
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Analyzed magnetometer and auroral optical data
demonstrated that disturbances span wide regions
of the globe and identified characteristics of magnetic
storms and substorms.
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NAPE volumes 1 and 2 published in 1908 and 1913
801 pages in English
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Birkeland calculated that millions of Amperes flow
in the upper atmosphere during disturbances.
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Argued that such large currents must be driven by
Sun and transmitted via field-aligned currents.
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After decades of hot debate field-aligned currents first
observed by TRIAD satellites in 1967
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Space Weather
Historical Roots
Fredrik Carl Mülertz Størmer
• 1874: born in Skien
• 1887 - 1897: High school and university education (1st publication in HS)
• 1898 - 1900: Postgraduate Research in France & Germany
- published about 10 paper in pure mathematics
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1902: elected member of The Norwegian Academy
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1903: appointed Professor of Pure Mathematics
1904: begins particle trajectory in magnetic dipole calculations
1910, 1913: auroral expeditions to Bossekop
1957: died in Oslo
~ 300 scientific papers (more than 50 in Comptes Rendus)
Auroral Atlas (1930, 1934, 1951) and The Polar Aurora (1953)
4 nominations for Nobel Prize in Physics with Kr. Birkeland
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Space Weather
Historical Roots
Størmer's Contributions to Auroral Physics:
• Calculated trajectories allowed energetic charged particles
in dipole representation of Earth’s magnetic field
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Enticed by Birkeland’s terrella experiments (1904)
Solved trajectories of all possible particles numerically
Demonstrated forbidden and allowed regions
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Cosmic ray access to Earth
Van Allen radiation belts
Predicted ring current during magnetic storms
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Space Weather
Historical Roots
Størmer's Contributions to Auroral Physics:
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Determined auroral heights classes and locations
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With Krogness developed first camera to photograph aurorae
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Established auroral network in southern Norway
Conducted auroral expeditions to Bossekop in 1910 and 1913
Developed physical /analytical tools to conduct parallactic
measurements of auroral features
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Aurorae do not penetrate below 90 km, can reach 1,000 km
Align in the magnetic east-west direction
Normally near magnetic latitudes of 67° but in storms move to about 57°
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Space Weather
Historical Roots
Some Conclusions
• Decades before entry into space European scientist were investigating
phenomena that occur in the atmosphere above 100 km that reflect the
variability of our space environment
• Birkeland’s field-aligned current model first suggested how energy from
the Sun electrically couples to Earth’s upper atmosphere.
• Størmer's analysis of allowed particle trajectories anticipated properties
cosmic rays and the radiation belts discovered decades later.
• Størmer's parallactic photography provided the first systematic basis for
understanding the structure of the upper atmosphere.
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