How does energy from magnetic storms get transferred from high to low latitudes Anthea Coster, MIT Haystack Observatory How does energy from magnetic storms get transferred from high to low latitudes Anthea Coster, MIT Haystack Observatory

Outline Introduction to Storm Effects Introduction to Storm Effects Storm-Time Electric Fields Storm-Time Electric Fields Penetration Electric Fields Penetration Electric Fields Disturbance Dynamo Disturbance Dynamo Storm time Neutral Effects Storm time Neutral Effects Winds – TADs/TIDs Winds – TADs/TIDs Composition Effects Composition Effects Summary Summary

Astronomy Picture of the Day 17 September 2012 Picture of a long standing solar filament suddenly erupted into spacesolar filament producing an energetic Coronal Mass Ejection (CME) Coronal Mass Ejection

Solar EUV Effects: No Magnetic Fields M-I coupling After J. Grebowsky

Addition of Earth’s Magnetic Field M-I coupling After J. Grebowsky

Addition of Solar Wind and IMF M-I coupling After J. Grebowsky

Storm Effects Charged particle precipitation in the auroral zone Charged particle precipitation in the auroral zone Significant enhanced plasma convection at high latitudes Significant enhanced plasma convection at high latitudes Penetration of electric fields into middle and low latitudes Penetration of electric fields into middle and low latitudes Steepened mid-latitude ionospheric trough Steepened mid-latitude ionospheric trough Storm-time Enhanced Density (SED) Storm-time Enhanced Density (SED) Ionospheric Undulation and irregularities at subauroral latitudes Ionospheric Undulation and irregularities at subauroral latitudes Enhanced equatorial anomaly Enhanced equatorial anomaly Auroral electron jet Auroral electron jet Joule heating and friction heating Joule heating and friction heating Heating in the high-latitude thermosphere Heating in the high-latitude thermosphere Traveling atmospheric disturbances (TADs); Traveling ionospheric disturbances (TIDs) Traveling atmospheric disturbances (TADs); Traveling ionospheric disturbances (TIDs) Enhanced equatorward wind Enhanced equatorward wind Positive storm effects Positive storm effects Possibly suppressing equatorial irregularities Possibly suppressing equatorial irregularities Global thermospheric circulation change Global thermospheric circulation change Thermospheric composition change: negative storm effects Thermospheric composition change: negative storm effects Erosion of the plasmasphere Erosion of the plasmasphere

How does energy from magnetic storms get transferred from high to low latitudes ?? The Answer Electric Fields Electric Fields Penetration Electric Fields Penetration Electric Fields Disturbed Dynamo Electric Fields Disturbed Dynamo Electric Fields Neutral Effects Neutral Effects Enhanced Winds (Auroral Heating) Enhanced Winds (Auroral Heating) Neutral Composition Changes (O/N2) Neutral Composition Changes (O/N2)

References Definition of Storm-Time Penetration Electric Fields: Chaosong Huang, Stanislav Sazykin, Robert Spiro, Jerry Goldstein, Geoff Crowly, J. Michael Ruohoniemi [EOS, 87(13),doi: /2006EO130005, 2006] Definition of Storm-Time Penetration Electric Fields: Chaosong Huang, Stanislav Sazykin, Robert Spiro, Jerry Goldstein, Geoff Crowly, J. Michael Ruohoniemi [EOS, 87(13),doi: /2006EO130005, 2006] The Sub-Auroral Polarization Stream (SAPS) as defined by Foster and Burke [EOS, 83(36), 393, 2002] The Sub-Auroral Polarization Stream (SAPS) as defined by Foster and Burke [EOS, 83(36), 393, 2002] The ionospheric disturbance dynamo, Blanc and Richmond, M. Blanc and A.D. Richmond, JGR 85 (1980) The ionospheric disturbance dynamo, Blanc and Richmond, M. Blanc and A.D. Richmond, JGR 85 (1980) Time dependent response of equatorial ionospheric electric fields to magnetospheric disturbances, Fejer, B. G., and L. Scherliess, Geophys. Res. Lett., 22, 851, Time dependent response of equatorial ionospheric electric fields to magnetospheric disturbances, Fejer, B. G., and L. Scherliess, Geophys. Res. Lett., 22, 851, 1995.

R. A. Heelis, Low and Middle Latitude Ionospheric Dynamics Associated with Magnetic Storms, AGU MIDD

21:00 UT Uplift Downwelling Guiana Key West

Storm-time Appelton Anomaly Mannucci et al., 2005, GRL

TEC Hole Enhanced Eq Anomaly Plume Bulge Enhanced TEC Region observed in the Mid-Latitudes

Outline Introduction to Storm Effects Introduction to Storm Effects Storm-Time Electric Fields Storm-Time Electric Fields Penetration Electric Fields Penetration Electric Fields Disturbance Dynamo Disturbance Dynamo Storm time Neutral Effects Storm time Neutral Effects Winds – TADs/TIDs Winds – TADs/TIDs Composition Effects Composition Effects Summary Summary

Mid-latitude F2 Layer is Uplifted The crucial point is that the increase in the ionization density is preceded by a significant increase in the height of the F2 layer ……… This prior uplifting of the ionosphere is typical and is almost always observed. Therefore, any explanation of positive ionospheric storms must be consistent with this observation. Prolss, Ionospheric Storms at Mid-Latitudes: A Short Review MIDD

Two Mechanisms for uplifting plasma in midlatitudes Prolss, Ionospheric Storms at Mid-Latitudes: A Short Review MIDD

Storm-time Electrodynamics During geomagnetically active time periods, electric fields in the ionosphere are thought to originate from: During geomagnetically active time periods, electric fields in the ionosphere are thought to originate from: a disturbed wind dynamo, and a disturbed wind dynamo, and those of magnetospheric origin those of magnetospheric origin Penetration Electric Field Penetration Electric Field Subauroral Polarization Stream Subauroral Polarization Stream Huang, et al., EOS, 2006

Penetration Electric Field vs. Disturbance Wind Dynamo The direct penetration of the high-latitude electric field to lower latitudes, and the disturbance, both play a significant role in restructuring the storm-time equatorial ionosphere and thermosphere. The direct penetration of the high-latitude electric field to lower latitudes, and the disturbance dynamo, both play a significant role in restructuring the storm-time equatorial ionosphere and thermosphere. Although the fundamental mechanisms generating each component of the disturbance electric field are well understood, it is difficult to identify the contribution from each source in a particular observation. Maruyama, N.; Richmond, A. D.; Fuller-Rowell, T. J.; Codrescu, M. V.; Sazykin, S.; Toffoletto, F. R.; Spiro, R. W.; Millward, G. H Maruyama, N.; Richmond, A. D.; Fuller-Rowell, T. J.; Codrescu, M. V.; Sazykin, S.; Toffoletto, F. R.; Spiro, R. W.; Millward, G. HMaruyama, N.Richmond, A. D.Fuller-Rowell, T. J.Codrescu, M. V. Sazykin, S.Toffoletto, F. R.Spiro, R. W.Millward, G. HMaruyama, N.Richmond, A. D.Fuller-Rowell, T. J.Codrescu, M. V. Sazykin, S.Toffoletto, F. R.Spiro, R. W.Millward, G. H

Disturbed Dynamo vs. Penetration Electric Fields Both penetration and neutral disturbance dynamo electric fields occur at low latitudes during magnetic storms. Both penetration and neutral disturbance dynamo electric fields occur at low latitudes during magnetic storms. For the first several hours, penetration electric fields can cause ionospheric disturbances simultaneously at all latitudes and dominate the dayside ionospheric evolution. For the first several hours, penetration electric fields can cause ionospheric disturbances simultaneously at all latitudes and dominate the dayside ionospheric evolution. In contrast, large-scale atmospheric gravity waves take two to three hours to travel from the auroral zone to the equatorial ionosphere, and a significant propagation delay can be identified at different latitudes. In contrast, large-scale atmospheric gravity waves take two to three hours to travel from the auroral zone to the equatorial ionosphere, and a significant propagation delay can be identified at different latitudes. Huang, et al., EOS, 2006

Fejer, 2002 Full electrodynamical scenario for the EIA during a geomagnetic disturbance

Outline Introduction to Storm Effects Introduction to Storm Effects Storm-Time Electric Fields Storm-Time Electric Fields Penetration Electric Fields Penetration Electric Fields Disturbance Dynamo Disturbance Dynamo Storm time Neutral Effects Storm time Neutral Effects Winds – TADs/TIDs Winds – TADs/TIDs Composition Effects Composition Effects Summary Summary

How do the magnetosphere and ionosphere communicate? E. Yizengaw  Can flow along the magnetic field (FAC)  Connect the magnetosphere to the ionosphere R2-current R1-current Through Currents Ionospheric currents -

Ionosphere Currents

Storm-time Electric Fields Magnetospheric convection is enhanced following a southward turning of the interplanetary magnetic field (IMF). The initial high-latitude electric field will penetrate to the equatorial latitudes Strong storm-time penetration eastward electric field uplifts equatorial ionosphere Strong storm-time penetration eastward electric field uplifts equatorial ionosphere Enhances the Equatorial Anomaly Enhances the Equatorial Anomaly Cross-tail electric fields energize and inject particles into the inner magnetosphere forming the disturbance Ring Current Cross-tail electric fields energize and inject particles into the inner magnetosphere forming the disturbance Ring Current Sub-auroral polarization Stream forms – which is an electric field that is radially outward at the equator and poleward at higher latitudes. Where the SAPS field overlaps the region of enhanced electron density in the mid-latitudes Sub-auroral polarization Stream forms – which is an electric field that is radially outward at the equator and poleward at higher latitudes. Where the SAPS field overlaps the region of enhanced electron density in the mid-latitudes Storm-Enhanced Density (SED) Storm-Enhanced Density (SED)

Figure courtesy of J. Foster

Sample Results from Coupled SAMI3/RCM Code (R. Wolf) Plots show differences in height of F2 peak and Total Electron Content between - Storm case: 80 kV jump in the polar-cap potential assumed in RCM (from 40 kV to 120 kV) - No storm case: No jump in the polar-cap potential (remains constant at 40 kV) Penetration electric fields raised F2 peak by more than 100 km in post-dusk sector. Fountain effect depleted equatorial ionosphere and strengthened Appleton peaks.

Outline Introduction to Storm Effects Introduction to Storm Effects Storm-Time Electric Fields Storm-Time Electric Fields Penetration Electric Fields Penetration Electric Fields Disturbance Dynamo Disturbance Dynamo Storm time Neutral Effects Storm time Neutral Effects Winds – TADs/TIDs Winds – TADs/TIDs Composition Effects Composition Effects Summary Summary

Fast and Slow Wind Maximum conductivity: Transverse conductivity, especially Hall, confines to a rather narrow range of height (~ 125 km), the so called dynamo layer Produced by movement of charged particles of the ionosphere across B Motion is driven by the tidal effects of the Sun and the Moon and by solar heating. The ionospheric dynamo is thus controlled by two parameters: the distribution of winds and the distribution of electrical conductivity in the ionosphere. Ionospheric Dynamo

Why do we care about conductivities? Ionosphere is a plasma with an embedded magnetic field. “The resulting electric field is as rich and complex as the driving wind field and the conductivity pattern that produce it”, Kelley, Ch. 3

Basic Principles from Rod Heelis, CEDAR 2001 In a partially ionized plasma in a magnetic field the charged particle motion is anisotropic. It is determined by the distribution of charged and neutral particles. In a partially ionized plasma in a magnetic field the charged particle motion is anisotropic. It is determined by the distribution of charged and neutral particles.THUS: Forces may drive ions and electrons at different speeds producing a current that may have a divergence Forces may drive ions and electrons at different speeds producing a current that may have a divergenceBUT: Polarization electric fields are produced to make the total current divergence free everywhere. Polarization electric fields are produced to make the total current divergence free everywhere.THEN: Modified electric fields redistribute the ionization and change the anisotropic motions. Modified electric fields redistribute the ionization and change the anisotropic motions.

Equations of Motion Perpendicular equation of motion Parallel equation of motion

Conductivity Pedersen conductivity (along E ┴ ) perpendicular B, parallel E; horizontal Hall conductivity (along E x B) Parallel conductivity Conductivity tensor

Collision Frequencies Ion and electrons collide with neutrals as they gyrate. How they move in response to electric fields depends very much on the collision frequency relative to the gyro-frequency. Ion and electrons collide with neutrals as they gyrate. How they move in response to electric fields depends very much on the collision frequency relative to the gyro-frequency.

Points to Remember Hall conductivity in a layer near 125 km (along E x B) Hall conductivity in a layer near 125 km (along E x B) Essentially removed at night Essentially removed at night Pedersen conductivity distributed in two regions (perpendicular B, parallel E; horizontal) Pedersen conductivity distributed in two regions (perpendicular B, parallel E; horizontal) E-region much greater than F-region during the daytime E-region much greater than F-region during the daytime F region much greater than E region at night. F region much greater than E region at night. Direct conductivity much greater than transverse conductivities everywhere above 90 km. Direct conductivity much greater than transverse conductivities everywhere above 90 km. For spatial scales larger than 10 km, magnetic field lines are almost electric equipotentials even though field-aligned currents flow. For spatial scales larger than 10 km, magnetic field lines are almost electric equipotentials even though field-aligned currents flow.

Thermospheric Winds and Tides Thermospheric Neutral Winds Thermospheric Neutral Winds Tides – Largest atmospheric tides are the diurnal and semidiurnal tides driven by solar heating; Next is the semidiurnal gravitational tide. Tides – Largest atmospheric tides are the diurnal and semidiurnal tides driven by solar heating; Next is the semidiurnal gravitational tide. Tidal oscillations propagate upward, and associated wind speed amplitude grows Tidal oscillations propagate upward, and associated wind speed amplitude grows Diurnal tides can propagate vertically only below 30 o degrees latitude Diurnal tides can propagate vertically only below 30 o degrees latitude Semi-diurnal tide is dominant at latitudes greater than 30 o degrees latitude (mid-latitudes) Semi-diurnal tide is dominant at latitudes greater than 30 o degrees latitude (mid-latitudes)

Disturbance Dynamo Observed features of mid and low-latitude electric fields during storms could not always be explained by penetration electric fields. Observed features of mid and low-latitude electric fields during storms could not always be explained by penetration electric fields. Auroral Heating produces equatorward driven winds Auroral Heating produces equatorward driven winds Energy input into the thermosphere during geomagnetic storms alters the global thermospheric circulation and consequently alters the generation of electric fields and currents at middle and low latitudes by ionospheric wind dynamo action. Energy input into the thermosphere during geomagnetic storms alters the global thermospheric circulation and consequently alters the generation of electric fields and currents at middle and low latitudes by ionospheric wind dynamo action.

Outline Introduction to Storm Effects Introduction to Storm Effects Storm-Time Electric Fields Storm-Time Electric Fields Penetration Electric Fields Penetration Electric Fields Disturbance Dynamo Disturbance Dynamo Storm time Neutral Effects Storm time Neutral Effects Winds – TADs/TIDs Winds – TADs/TIDs Composition Effects Composition Effects Summary Summary

Wind surges, and changes in the global circulation, have been shown to reach the equator and propagate into the opposite hemisphere (Fesen et al., 1989). The composition changes driven by the winds are also expected to influence the region (Field et al., 1998). Fuler-Rowell et al., 2002

IMAGE O/N2 Observations – Day 1 of Storm ZHANG et al., 2004 IMAGE O/N2 Observations – Day 1 of Storm ZHANG et al., 2004

IMAGE O/N2 Observations – Day 1 & 2 of Storm ZHANG et al., 2004 IMAGE O/N2 Observations – Day 1 & 2 of Storm ZHANG et al., 2004

Outline Introduction to Storm Effects Introduction to Storm Effects Storm-Time Electric Fields Storm-Time Electric Fields Penetration Electric Fields Penetration Electric Fields Disturbance Dynamo Disturbance Dynamo Storm time Neutral Effects Storm time Neutral Effects Winds – TADs/TIDs Winds – TADs/TIDs Composition Effects Composition Effects Summary Summary

Mechanisms contributing to energy transfer … *Positive Storms at Mid- Latitudes Prolss, Ionospheric Storms at Mid-Latitudes: A Short Review MIDD