The Sun- Solar Activity

Damage to communications & power systems

Sunspots a dark area of the photosphere of the sun that is cooler than the surrounding areas due to the change in the convection of gasses caused by its strong magnetic field.

Sunspot cycle The number of sunspots increases and decreases through an 11 year cycle. Sunspots appear midway between the equator and poles and move toward the Sun’s equator as the number of spots increases. The cycle begins when the number of spots are at their lowest and peaks when the number reaches an maximum & starts to decrease again.

Solar Ejections Occur when the sun emits charged atomic particles (Positrons). Related to the magnetic field changes that cause sunspots, so they are the most frequent when the number of sunspots is high. Include: Prominences, Solar Flares, & Coronal Mass Ejections

Prominences a loop of relatively cool, glowing gas that extends above the photosphere and above the sun’s edge as seen from Earth.

Formation of Solar flares & Coronal loops Caused when there are differences in charge between the magnetic fields of 2 sunspots. Charged particles rush from one to the other forming a coronal loop. If this detaches, it is called a solar flare.

Coronal Mass Ejections Coronal gas that is thrown into space from the sun

Solar winds Prominences, Solar flares & Coronal mass ejections can all cause Solar winds. The solar wind is a stream of charged particles (mostly high-energy positrons resulting from nuclear fusion) which are ejected from the sun and move throughout space at a high speed.

Geomagnetic Storms A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in space weather due to solar winds. Solar winds cause shock waves which typically strike the Earth’s magnetic field 24 to 36 hours after the event. This only happens if the shock wave travels in a direction toward Earth. When these storms strike the ionosphere the Earth’s magnetic field is disrupted and overloading of electrical charges can occur. These 2 effects can cause disruption and/or damage to communications systems, navigation systems, satellites & power grids. Another effect of these storms interacting with the ionosphere are auroras.

Auroras Occur when the gasses in the ionosphere are excited by concentrated amounts of charged particles that occur during a geomagnetic storm. They usually happen near the poles because that is where the charged particles are drawn towards due to the magnetic field of Earth.

Aurora Borealis (Northern Lights) Aurora Australis (Southern lights)

Auroras on other planets Jupiter Saturn