The coupling of the Solar-terrestrial systems

Earth’s internal structure, atmospheric structure, and magnetosphere Solar General Structure Solar activity at or above the photosphere Space Weather Unit Outline

Earth structure

The Atmosphere

Geo-magnetism Sources for any natural magnet Imbalanced atomic dipole moments result in orientation of field lines and bulk magnetic properties of some elements and compounds. Geomagnetism a form of ferromagnetism resulting from the atomic properties of the iron, cobalt, and nickel that make up the internal portions of the earth as well as the coupling forces of the crystal lattices in the solid state which serve to align the atomic dipoles and generate bulk magnetic fields. Further reading on magnetism

Complex Fields that are ever changing Images on wikipedia common media license

Solar Structure

General Structure Radius690,000 km Average Density 1410 kg/m 3 Surface Temp5780 K Luminosity3.86 x W The sun contains no solid matter Light we ‘see’ is from photosphere (very thin, 500 km thick) This gives the sun the appearance of having a sharp edge to it.

Interior Model Assume Hydrostatic Equilibrium Outward pressure of hot gas balances the inward pull of gravity Outward force = inward force General Structure

Patterns of Density and Temperature Both decrease with distance from the core General Structure

Evidences of internal structure Spectral lines of certain elements are doppler shifted General Structure Images on wikipedia common media license

Evidence of internal structure Surface of the sun oscillates or vibrates with certain frequency Surface patterns result from internal pressure waves that reflect off of the photosphere Propagation of these pressure waves through the interior allows scientists to model the density and temperature profiles as well as internal movement of material. General Structure Images on wikipedia common media license

Evidence cont. From the photospheric expression of moving (doppler shifted) gas, we can map out the internal structure Models match observations quite well General Structure Images on wikipedia common media license

Active features of the photosphere Sunspots appear dark because slightly cooler than surroundings. Images on wikipedia common media license

9.4 The Active Sun Sunspots come and go, typically in a few days. Sunspots are linked by pairs of magnetic field lines. Active features of the photosphere

9.4 The Active Sun The Sun has an 11-year sunspot cycle, during which sunspot numbers rise, fall, and then rise again. The Active Features of the Photosphere

9.4 The Active Sun This is really a 22-year cycle, because the spots switch polarities between the northern and southern hemispheres every 11 years. Maunder minimum: few, if any, sunspots. The Active Features of the Photosphere Images on wikipedia common media license

The Active Features of the Photosphere Areas around sunspots are active; large eruptions may occur in photosphere. Solar prominence is large sheet of ejected gas. /

9.4 The Active Sun The rotation of the Sun drags magnetic field lines around with it, causing kinks. A Prominence can be seen when a loop is near the edge. Active features of the photosphere

A Solar flare is a large explosion on Sun’s surface, emitting a similar amount of energy to a prominence, but in seconds or minutes rather than days or weeks. /

A coronal mass ejection emits charged particles that can affect the Earth. /

9.4 The Active Sun Solar wind escapes Sun mostly through coronal holes, which can be seen in X-ray images. /

9.4 The Active Sun Solar corona changes along with sunspot cycle; is much larger and more irregular at sunspot peak.

Solar wind – a fast moving flux of radiation and charged particles interacting with earth’s magnetic field. "Parts of the Sun." SOHO-Gallery. Web. 01 Aug

Solar inputs and Earth’s Outputs

The paths of energy through the atmosphere Images on wikipedia common media license

Detection of a Solar Flare -Solar Flare events happen in stages -The first stage, or the precursor stage, the build-up of magnetic energy triggers the event and can be seen via soft x-rays -The second stage, impulsive stage is where the massive amount of energy is released across almost all spectra -Especially the Radio Spectrum!!! Space Weather

The Ionosphere - As a boundary between the solar wind magnetosphere and atmosphere, it can be a sensor for the influence of space weather on the atmosphere Space Weather

Interactions of solar wind and earths magnetosphere Space Weather

Coronal Mass Ejections (CMEs) -Often associated with solar flares -Extremely large ejections of solar wind and energy -Has a larger push on Earth’s magnetosphere than normal causing more extreme disturbances in our upper atmosphere - t_1,_2010.OGGhttp://en.wikipedia.org/wiki/File:Solar_Storm_on_Augus t_1,_2010.OGG - up_on_launching_filament_%28SDO- AIA,_304_%C3%85%29.ogvhttp://en.wikipedia.org/wiki/File:Close- up_on_launching_filament_%28SDO- AIA,_304_%C3%85%29.ogv - on_strikes_the_Earth.ogvhttp://en.wikipedia.org/wiki/File:A_Coronal_Mass_Ejecti on_strikes_the_Earth.ogv Space Weather

Case Study: The 2003 Halloween Storm This solar CME caused a massive geomagnetic storm that resulted in power outages in northern Europe. "Parts of the Sun." SOHO-Gallery. Web. 01 Aug Space Weather

Aurora Borealis (The Northern Lights) Space Weather Images on wikipedia common media license

The Halloween storm of 2003 created many disturbances in the atmosphere were studied for years afterward Space Weather

Two methods: Ionosonde Use radar from the ground or from satellite. A huge pulse of radio waves (Megawatts) is reflected off of ionosphere Return signal contains information about the structure, temperature, and ion content of the ionosphere. Studying the Ionosphere with Radio waves Image from:

Use current GPS/GNSS system For GPS navigation our receivers are constantly sending radio signals back and forth from the satellites. The ionosphere interferes with these signals and the level of interference can be used by scientists to estimate properties of the ionosphere. Studying the ionosphere with Radio A. Coster 2013 MIT Haystack

Geospace environment includes solar inputs of radiation and high energy particles Variations in the solar wind from events like CMEs, flares, promenances, faculae,…. May cause geomagnetic disturbances or storms Monitoring the ionosphere is important for understanding the effect of solar variability on earths environment for engineering purposes as well as climate change. Summary

References Free GNU license agreement "Parts of the Sun." SOHO-Gallery. Web. 01 Aug Hathaway, David H. "Sun Spot Cycles." NASA/Marshall Solar Physics. NASA/Marshall, 4 July Web. 04 Aug "Climate and Earth’s Energy Budget : Feature Articles." Climate and Earth’s Energy Budget : Feature Articles. Web. 08 Aug

Shapley, Patricia. "Our Energy Budget." Our Energy Budget. University of Illinois, Web. 08 Aug