Introduction to Space Physics & Space Instrumentation
Course Overview & Scope of Space Plasma Physics EAS 4360/6360
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Outline What is Space Physics? Course Structure & Assessments Motivation A Brief Early History Overview of Course Topics Concluding Remarks
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What is Space Physics? The physics of plasmas in the solar system. Encompasses from the solar interior out to the Interstellar Medium. Astrophysics of the solar system
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What is Space Physics? Solar and heliospheric physics - the study of the Sun and solar variability and of the composition, structure, and dynamics of the interplanetary medium and its interaction with the local interstellar medium. Magnetospheric physics - the study of the plasmas, magnetic and electric fields, and current systems in the magnetospheres of the Earth and other planets. Aeronomy - the study of the ionized and neutral upper atmospheres of the Earth and planets and of their interactions with their respective space environments. EAS 4360/6360
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Course Structure & Assessment
MWF Lectures……………………….… 5% Roughly 8 graded HW sets .…………. 30% One Midterm & Final …………….…… 35% Final Project …………………………… 30% Consisting of: A term project ……….…. 25% An oral presentation……. 5%
Office Hours -- Directly after class on Mondays
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Course Structure & Assessment HW Policies -HW assignments will be due at the beginning of class one week after assigned. Late homework turned in by the following class will be deducted 20%. No credit will be given for assignments later than this deadline unless exceptional circumstances are demonstrated. I encourage you to work together as it can be quite beneficial, but everyone must turn in their own work. EAS 4360/6360
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Course Structure & Assessment Website: The course website will have the syllabus, all powerpoint notes, handouts and assignments: http://shadow.eas.gatech.edu/~cpaty/courses/SpacePhysics2013/
Textbook: Basic Space Plasma Physics by W. Baumjohann & R. A. Treumann *** We will follow the formulation, but not necessarily the ordering/focus of the text. Please see the course website for a list of supplemental texts that you may find useful. EAS 4360/6360
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Motivation
Space Weather implications… living with a star. Natural laboratory for observing, studying, and testing theory for Space Plasmas. Comparative planetology ⇒ understanding the role of space plasmas on atmospheric evolution and habitability, as well as the evolution and importance of planetary magnetic fields.
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NASA, GSFC
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A Brief Early History Satellites -- 02/1/1958 (Explorer 1) to present, but that was far from the beginning.
Aurora
Observed/speculated on for thousands of years. Detailed documentation 1582-1598 by Tycho Brahe illustrated year to year variation. Altitude roughly determine in 1621 by correlated observations by Galileo and Gassendi. Later more accurately calculated by de Mairan (1726) and Cavendish (1790), and definitively by Stormer (1900) using photographic techniques. Cpt. Cooke ‘first’ to discover the southern lights (1773).
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A Brief Early History
Accounts of auroral occurrence collected from polar explorers helped determine their longitudinal & latitudinal extent (Munke in 1883), formally mapped into an auroral zone by Elias Loomis in 1860.
Loomis, 1860
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Late 1890s
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A Brief Early History Geomagnetic Field
First simple compass described in 1088 by Shen Kua. Again by Neckham a century later. Robert Norman discovers the vertical component of the Earth’s magnetic field in 1576. De Magnete (1600) by W. Gilbert discussed the behavior of the Earth’s field as a magnet, allowing for globally mapping field orientation relative to location and enabling global navigation via compass. Ultra sensitive compass developed by Graham in 1721 enable observation of slight irregular variations of the field.
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A Brief Early History Drewitt,1905
Solar Activity Galileo 1610?
In 1610 Galileo discovers sunspots using a new technology… a telescope. While observed slightly earlier and simultaneously by several others, only GG correctly postulated that they were on the surface of the Sun.
After compiling ~18 years of sunspot tracking data, S.H. Schwabe determined an 11 year solar cycle in ~1844. In 1893 Maunder tried to extrapolate this cycle from older observations and discovered a true minimum in the count between 1645-1715.
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A Brief Early History
Maunder minimum was correlated to a lack of corona observed during eclipse and later to a low in historic aurora accounts. But what exactly were sunspots?
R. Rohde, Global Warming Art project
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A Brief Early History Pulling it all together…
Edmond Halley first noted that aurora seemed to have rays that converge toward Earth similar to the geomagnetic field in 1716, but this correlation was not confirmed until 1770 by J. Wilke.
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Courtesy of skychasers.net
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A Brief Early History
Graham’s magnetic irregularities, coined ‘geomagnetic activity,’ were correlated to aurora by Anders Celsius, and together they found that such activity was correlated over large distances (England to Sweden) as well. Sabine and Wolf independently determined correlation between sunspots and geomagnetic activity in the 1850s. Due to difficulty observing aurora reliably, it would take many more years to directly link aurora to solar activity.
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A Brief Early History
How were sunspots linked to the Earth’s magnetic field? In 1859 Richard Carrington observed a flare of light above a sunspot, followed by geomagnetic activity a day later… However, the lack of understanding of subatomic particles, corpuscular radiation, linkages between electricity and magnetism, and the assumption that space was a pure vacuum made this coincidence difficult to explain for several more decades.
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Overview of Course Topics
Courtesy of Goddard Conceptual Image Lab EAS 4360/6360
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Overview of Course Topics
Introduction to Space Plasmas Active Sun & Solar Cycle Solar Wind & Interplanetary Medium Interaction of the Solar Wind with Solar System Bodies Magnetic Reconnection Instrumentation
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Overview of Course Topics
Physics of the Magnetosphere Space Weather & Solar-Terrestrial Physics Ionosphere & Aurora Inner Magnetosphere Plasmas & Electrodynamics Magnetospheres of other Planets Atmospheres of other Planets Heliosphere & Interstellar Medium
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Concluding Thoughts Next lecture: Introduction to Space Plasmas Reading for this week: Chapters 1 through 2.2 of Baumjohann & Treumann Before you leave: A few minutes to fill out the ‘survey’
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