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Earth’s Magnetosphere Space Weather Training Kennedy Space Center Space Weather Research Center
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Magnetic Field of the Earth The Earth's magnetic field is similar to that of a bar magnet. The magnitude varies over the surface of the Earth in the range 0.3 to 0.6 Gauss.
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Earth’s Magnetic Field – Our Shield (not to scale) Magnetosphere Earth Magnetopause Sub-solar point The solar wind pushes and stretches Earth’s magnetic field into comet-shaped region called the magnetosphere. The magnetosphere and Earth’s atmosphere protect us from the solar wind and other kinds of solar and cosmic radiation.
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Spatial Scales Magnetosphere Earth 1 R E (Earth’s radius) = 6370 km 1 R S (Solar radius) ~ 110 R E 1 AU (Distance between the Sun and the Earth ) ~ 215 R S
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Magnetosphere for Southward and Northward IMF Orientation Magnetic Reconnection
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Magnetosphere for Southward and Northward IMF Orientation
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Magnetosphere: Northward IMF X: Earth to Sun Z: South to North Z X
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Magnetosphere: Southward IMF
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Magnetosphere: North to South Turning
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meridional cut Y=0 equatorial cut Z=0 cross-tail cut X= -15 R E Magnetotail current sheet Magnetopause Magnetotai l Bow shock
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Magnetosphere: Quiet vs. Compressed Geosynch. orbit Magnetopause
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Magnetopause Stand-off Distance r0 <=6.6 Re – model product Events: Apr 5, 2010, Dec 28, 2010 Jan 6, 2011, 22:30 UT Non-event: Dec 1 – 7, 2010 Degree of compression of MP Due to Pdyn of solar wind (interplanetary shock or HSS)
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Kp Geomagnetic activity index range from 0-9 disturbance levels of magnetic field on the ground - currents 1.Non-event - period of 12/01/2010 – 12/7/2010 2.Moderate event – April 5, 2010 3.Extreme event - Oct 29 – Oct 31, 2003 "planetarische Kennziffer" ( = planetary index). Threshold Kp>=6 http://bit.ly/Kp_layout
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Inner Magnetosphere (up to ~ 10 RE) APL Plasmasphere Ring Current Van Allen Belts 1-10 eV 1-400 keV 400 keV – 6 MeV
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Inner Magnetosphere Plasmas
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Electron Total Flux. Energy 63.3 keV. Color Contour Earth radius Equatorial Plane Magnetopause Geosynch. Orbit
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Ring Current: Quiet vs. Active
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Horne et al., 2007, Nature Physics
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Magnetic Storms
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Substorms
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Space weather impacts (credit: L. Lanzerotti/Bell Labs) Space Weather Impacts
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Lagrange Point – L1 L1 (Solar Wind Monitor ACE location): ~ 200 R E sunward You can fit 1 Sun between the Earth and L1. 2 R S (Solar diameter) ~ 220 R E A dvanced C omposition E xplorer
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Solar Wind Speed at ACE
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Solar Wind Parameters at ACE on 04/05/2010 nT km/s part/cm 3 Magnetic field B x, B y, B z Velocity Density X: Earth to Sun Z: North to South
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Magnetopause Stand-off Distance Degree of compression of MP due to dynamic pressure of solar wind March 17, 2015
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Kp index Geomagnetic activity index - range from 0-9 disturbance levels of magnetic field on the ground – currents "planetarische Kennziffer" ( = planetary index). Threshold Kp>=6
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HSS and Radiation Belt Electron Flux Enhancement NASA/GSFC, internal use only :-)
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Energetic Proton Flux >10 MeV flux by GOES spacecraft Threshold: 10 pfu >100 MeV flux by GOES spacecraft Threshold: 1 pfu
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Watch the video http://missionscience.nasa.gov/sun/ sunVideo_04magnetosphere.html
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iSWA Layout: 07/12/2012
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