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What DMSP Data Tell us About the Thermosphere Response to Solar Wind Forcing Delores Knipp CU Aerospace Engineering Sciences and NCAR HAO With Assistance from Liam Kilcommons, CSU
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What DMSP Data Tell us About the Thermosphere Response to Solar Wind Forcing - Energy deposition on the dayside can be strongly controlled by the IMF By component -Even during strong storms energy deposition on the dayside may exceed that on the nightside -Orbit Integrated Poynting flux (and DMSP B) show the physical link between solar wind and neutral density periodicities - During strong IMF By events magnetosheath particles are supplementing the energy deposition by Poynting flux…..but at a different altitude - During high speed streams energy deposition on the dayside dominates that on the nightside
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Adapted from Day, C., Spacecraft probes the site of magnetic reconnection in Earth's magnetotail, Physics Today, Vol. 54, No. 10, 16-17, 2001. Adapted from NASA Press release: Connection of Sun's and Earth's magnetic fields provides energy for auroras, space weather, 2000. Southward IMFNorthward IMF Schematics of magnetopause reconnection for IMF Bz illustrating the topological differences in reconnection location, depending upon the interplanetary magnetic field direction.
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Park et al., 2006 Merging location simulation with dipole tilt of 30, IMF Bz = –5 nT, and IMF By = 5 nT. 0 180 90270
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When IMF Bz is negative and By is present Merged flux tubes are accelerated azimuthally, Dayside flow channel s develop between convections cells R1 field aligned currents become asymmetric near noon – Negative (dawnward) west, Those connected to the southern (northern) hemisphere move duskward (dawnward) Downward R1 currents dominate the noon sector in the northern hemisphere - Positive (duskward) east, Those connected to the southern (northern) hemisphere move dawnward (duskward) Upward R1 currents dominate the noon sector in the northern hemisphere N N (Weimer, 2005 and Anderson, et al. 2008) 0 180 90 270 0 180 90 270
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0 180 90 270 0 180 90 270 When IMF Bz is positive and By is present Merged flux tubes are accelerated azimuthally, Dayside flow channel s develop but appear to be more variable R1 field aligned currents become asymmetric near noon, R0 field aligned currents may be present Strong IMF and high speed flow may provide more clarity (Weimer, 2005 and Anderson, et al. 2008)
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Poynting Vector from Defense Meteorological Satellite Program S/C DMSP instruments sense Electric and Magnetic Fields Y X Z Spacecraft track
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Cusp reconnection near the dawn flank Field lines map across dayside Near-Cusp energy source during strong IMF By: Li et al. Southern lobe field lines Obs DMSP Mag Perturbations Calculated DMSP Poynting Flux OPENGGCM Joule Heating SH SH B z ~+10nT B Y ~+25nT V SW ~ 950 km/s OPENGGCM FAC 0 180 90 270
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Poynting Flux Delta BxDelta By Vy DMSP Data and Calculations
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Aug 24 2005 Large IMF By, Bz~0 Neutral Density Crowley et al., 2010
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Poynting FluxParticle Flux Vz DMSP Data and Calculations ….not quite the full story…..
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High-Latitude Energy Input: Field and Particles Poynting FluxParticle Flux
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Poynting FluxParticle Flux Vz DMSP Data and Calculations ….not quite the full story…..
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2005 Poynting Flux and Solar Wind Speed Lomb-Scargle Periodogram
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DMSP F-15 Orbit Integrated |dB y | for 2005 Blue = angles in the range 90-180 , typical away or positive polarity. Red denotes angles in the range 270-360 ., typical toward or negative polarity. Yellow denotes angles in either of the other two azimuthal quadrants. Orbit Integrated dBy
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DMSP F-15 Orbit Integrated dB y for 2005 Blue = angles in the range 90-180 , typical away or positive polarity. Red denotes angles in the range 270-360 ., typical toward or negative polarity. Yellow denotes angles in either of the other two azimuthal quadrants. Orbit Integrated dBy
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Intense Magnetic Storm Jan 21-22 2005
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High-speed Stream August 15-16 2005
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AMIE Joule Heating and Electric Potential During High Speed Flow 00 UT 16 Aug 2005 Courtesy of G. Crowley
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AMIE Joule Heating and Electric Potential During High Speed Flow 04 UT 16 Aug 2005 Courtesy of G. Crowley
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AMIE Joule Heating and Electric Potential During High Speed Flow 1040 UT 16 Aug 2005 Courtesy of G. Crowley
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AMIE Joule Heating and Electric Potential During High Speed Flow 2045 UT 16 Aug 2005 Courtesy of G. Crowley
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What DMSP Data Tell us About the Thermosphere Response to Solar Wind Forcing - Energy deposition on the dayside is strongly controlled by the IMF By component -Even during strong storms energy deposition on the dayside may exceed that on the nightside -Orbit Integrated Poynting flux (and DMSP B) show the physical link between solar wind and neutral density periodicities - During strong IMF By events magnetosheath particles are supplementing the energy deposition by Poynting flux…..but at a different altitude - During high speed streams energy deposition on the dayside dominates that on the nightside
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