4% of the disturbances in the US power grid are due to geomagnetically .... The green lines show the magnetic perturbations over the northern hemisphere.
Can Power Outages on Earth Be Predicted by Observations of the Sun? Rajkumar Hajra1 Bruce T. Tsurutani2, Ezequiel Echer1, Walter D. Gonzalez1, Jesper W. Gjerloev3,4 1Instituto
Nacional de Pesquisas Espaciais, Sao Jose dos Campos, SP, Brazil 2Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA 3John Hopkins University of Applied Physics Laboratory, Laurel, MD 4Birkelan Center, University of Bergen, Norway
Supported by:V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
Power Outages & Space Weather •
Some power outages at Earth are associated with strong currents with amplitudes >106 Amp flowing in the ionosphere at ~100 km above the Earth’s surface.
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4% of the disturbances in the US power grid are due to geomagnetically induced currents: North American Electric Reliability Corporation (NERC)
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A flare on the Sun occurred on 1 September 1859. It led to a coronal mass ejection (CME) that caused the largest magnetic storm (Dst ~-1760 nT) in the recorded history at Earth, some ~17 hrs and 40 min after the flare occurred [Tsurutani et al., JGR, 2003]. It caused fires and electrical shocks associated with arcing from induced voltages on telegraph lines [Elias Loomis, Am. J. Sci., 1861]. At that time, telegraph communication was the “high technology” of the day. Imagine such a magnetic storm TODAY!!!
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V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
Magnetic storms are the biggest SunSunEarth space weather event that happens! • • •
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Magnetic storms are magnetospheric disturbances. They are characterized by enhanced particle fluxes in the radiation belts. The enhanced fluxes can be indirectly measured by decreases in the Earth’s magnetic field horizontal component caused by the diamagnetic effect generated by the ring current. A standard measure of this is the Dst index, which is proportional to the total kinetic energy of 20-200 keV particles within the outer radiation belt, thus it is a good quantitative measure of the intensity of the geomagnetic storm. The inner edge of the ring current is located at 4 RE or less from the Earth’s surface during intense storms. For lesser intensity storms, the ring current is located further away from the Earth.
V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
What Causes Magnetic Storms? Echer et al., JGR, 2008 Enhanced solar wind-magnetosphere energy coupling • Viscous interaction of the solar wind • Cross-field diffusion from magnetosheath to the magnetopause boundary layer by resonant waveparticle interaction • Magnetic reconnection between Earth’s northward magnetic field and southward interplanetary magnetic field (IMF Bz) Majority of intense storms are caused by magnetic clouds (MCs) and Sheath fields. July 2004
V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
Solar Flares, Flares, CMEs & Magnetic Storms are not ALL of Space Weather!!!
V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
Substorms •
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A substorm corresponds to an injection of charged particles from the magnetotail into the nightside magnetosphere. Plasma instabilities lead to precipitation of the particles into the auroral zone ionosphere, that excite atmospheric O2 and N2 resulting in luminous glow known as Aurora. Substorms are a magnetospheric and magnetotail processes that also have effects in the ionosphere. These are associated with flow of ionospheric currents, called auroral electrojets, which flow at an altitude of ~100 km above the Earth. >106 Amp currents may induce currents in conductors on the ground and cause overheating and sometimes explosions of transformers. In extreme cases, entire power grid outages may occur. V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
What Triggers Substorms? Shock arrival
Zhou & Tsurutani, JGR, 2001
24 September 1998
With southward IMF Bz preconditions, the substorm was triggered by Interplanetary Shock V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
What Causes the Largest Substorms in the Magnetosphere? Shocks? Let us see…..
V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
SuperSubStorms (SSSs) •
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During substorms, enhanced ionospheric conductivity and externally imposed electric fields lead to intensification of the auroral electrojets. We identify substorms using a global network of ground magnetic stations data called SuperMAG. The network covers midlatitude ionospheric currents which will be important during magnetic storms when the auroras and their associated currents move equatorward.
SuperMAG is a worldwide collaboration of organizations and national agencies that currently operate more than 300 ground based magnetometers.
SML < -2500 nT: “sUPERsUBsTORM”
V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
SSSs on 24 November 2001 km/s cm-3
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nT
Magnetic storm was ongoing in both cases (SYM-H index decreasing). Solar wind energy (identified by IMF Bs and ε) was being injected into the magnetosphere prior to both SSSs.
nT mV/m nPa
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Both the SSSs are time-coincident with pressure pulses.
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Pressure pulse is leading to the sudden release of recently injected and stored energy.
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This is typical of the study of the 37 SSSs that occurred during solar cycle 23 (1996-2008).
1011 W nT nT
V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
SSSs on 24 November 2001
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Polar images during two SSSs. The green lines show the magnetic perturbations over the northern hemisphere. Very large magnetic deviations over Alaska, northern Canada and northern Europe. V Simpósio Brasileiro de Geofísica Espacial e Aeronomia – SBGEA, 29 September-03 October 2014, Natal, Brazil
Summary •
Some power outages at Earth are associated with strong currents (>106 Amp) flowing in the ionosphere at ~100 km above the Earth’s surface.
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The biggest Sun-Earth space weather events are the geomagnetic storms.
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The magnetic reconnection from MC/sheaths causes the majority of magnetic storms.
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Interplanetary shocks may trigger nighttime substorms.
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Supersubstorms (SSSs) with SML
