Solar Storm

A solar storm is a term used for atmospheric effects felt on Earth from certain events that occur on the Sun. You probably think of the Sun as a bright shining light that never changes. In reality, it’s an unbelievably huge ball of molten gases that’s constantly in flux.

A solar storm is a disturbance on the Sun, which can emanate outward across the heliosphere, affecting the entire Solar System, including Earth and its magnetosphere, and is the cause of space weather in the short-term with long-term patterns comprising space climate.

Solar radiation storms occur when the Sun emits huge bursts of energy in the form of solar flares and coronal mass ejections. These phenomena send a stream of electrical charges and magnetic fields toward the Earth at a speed of about three million miles per hour.

The most important particles are protons which can get accelerated to large fractions of the speed of light. At these velocities, the protons can traverse the 150 million km from the sun to Earth in just 10’s or less.

When they reach Earth, the fast-moving protons penetrate the magnetosphere that shields Earth from lower-energy charged particles. Once inside the magnetosphere, the particles are guided down the magnetic field lines and penetrate into the atmosphere near the north and south poles.

Solar Radiation Storms cause several impacts near Earth. When energetic protons collide with satellites or humans in space, they can penetrate deep into the object that they collide with and cause damage to electronic circuits or biological DNA. During the more extreme Solar Radiation Storms, passengers and crew in high flying aircraft at high latitudes may be exposed to radiation risk.

Also, when the energetic protons collide with the atmosphere, they ionize the atoms and molecules thus creating free electrons. These electrons create a layer near the bottom of the ionosphere that can absorb High Frequency (HF) radio waves making radio communication difficult or impossible.

When a solar storm strikes the Earth, it often produces a dazzling NORTHERN LIGHTs display in parts of the atmosphere that can be seen in areas close to the Arctic Circle. Solar storms can also disrupt satellites and various forms of electronic communications.

Scientists who study solar storms have discovered that the frequency of solar flares appears to follow an 11-year solar cycle. At times of peak activity, there could be several solar storms each day. At other times, there might be less than one solar storm per week. Scientists expect the Sun’s current activity cycle to result in a peak in solar storms during 2024.

Solar Storm Includes:

1.Solar Flare, a large explosion in the Sun’s atmosphere

A solar flare is an intense burst of radiation coming from the release of magnetic energy associated with sunspots. Flares are our solar system’s largest explosive events. They are seen as bright areas on the sun and they can last from minutes to hours. 

We typically see a solar flare by the photons (or light) it releases, at most every wavelength of the spectrum. The primary ways we monitor flares are in x-rays and optical light. Flares are also sites where particles (electrons, protons, and heavier particles) are accelerated.

Solar flares occur in a power-law spectrum of magnitudes which release the energy of typically 1020 joules of energy suffices to produce a clearly observable event, while a major event can emit up to 1025 joules.

Flares occur when accelerated charged particles, mainly electrons, interact with the plasma medium. Evidence suggests that the phenomenon of magnetic reconnection leads to this copious acceleration of charged particles. 

On the Sun, magnetic reconnection may happen on solar arcades (a series of closely occurring loops following magnetic lines of force). These lines of force quickly reconnect into a lower arcade of loops leaving a helix of magnetic field unconnected to the rest of the arcade. The sudden release of energy in this reconnection is the origin of the particle acceleration.

The unconnected magnetic helical field and the material that it contains may violently expand outwards forming a coronal mass ejection. This also explains why solar flares typically erupt from active regions on the Sun where magnetic fields are much stronger.

2. Coronal Mass Ejection (CME), a massive burst of the solar wind, sometimes associated with solar flares

The outer solar atmosphere, the corona, is structured by strong magnetic fields. Where these fields are closed, often above sunspot groups, the confined solar atmosphere can suddenly and violently release bubbles of gas and magnetic fields called coronal mass ejections.

A large CME can contain a billion tons of matter that can be accelerated to several million miles per hour in a spectacular explosion. Solar material streams out through the interplanetary medium, impacting any planet or spacecraft in its path. CMEs are sometimes associated with flares but can occur independently.

A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the solar corona. They often follow solar flares and are normally present during a solar prominence eruption. The plasma is released into the solar wind and can be observed in coronagraph imagery.

The phenomenon of magnetic reconnection is closely associated with CMEs and solar flares. In magnetohydrodynamic theory, when two oppositely directed magnetic fields are brought together is called MAGNETIC RECONNECTION. Reconnection releases energy stored in the original stressed magnetic fields. These magnetic field lines can become twisted in a helical structure, with a ‘right-hand twist’ or a ‘left-hand twist’.

As the Sun’s magnetic field lines become more and more twisted, CMEs appear to be a ‘valve’ to release the magnetic energy being built up, as evidenced by the helical structure of CMEs, that would otherwise renew itself continuously each solar cycle and eventually rip the Sun apart.

On the Sun, magnetic reconnection may happen on solar arcades—a series of closely occurring loops of magnetic lines of force. These lines of force quickly reconnect into a low arcade of loops, leaving a helix of magnetic field unconnected to the rest of the arcade.

The sudden release of energy during this process causes the solar flare and ejects the CME. The helical magnetic field and the material that it contains may violently expand outwards forming a CME. This also explains why CMEs and solar flares typically erupt from what is known as the active regions on the Sun where magnetic fields are much stronger on average.

3.Coronal Cloud, the mass of plasma and particles ejecta of a CME after jettisoned from the Sun

A coronal cloud is the cloud of hot plasma gas surrounding a coronal mass ejection. It is usually made up of protons and electrons. When a coronal mass ejection occurs at the Earth’s Sun, it is the coronal cloud that usually reaches Earth and causes damage to electrical equipment and space satellites, not the ejection or flares itself. The damage is mostly the result of the high amount of electricity moving through the atmosphere.

A coronal cloud is released when a solar flare becomes a coronal mass ejection (the coronal cloud often contains more radioactive particles than the mass ejection itself). A coronal mass ejection occurs when a solar flare becomes so hot that it snaps and breaks in two, becoming a ROPE of heat and magnetism that stretches between two sunspots.

The resulting coronal mass ejection can be compared to a horseshoe magnet, the sunspots being the poles and the oscillating magnetic connector the handle. Coronal mass ejections typically do not last very long, because they cool down as the coronal cloud of gas is released and begins to hurtle away from the Sun.

4.Geomagnetic Storm, the interaction of the Sun’s outburst with Earth’s magnetic field

A geomagnetic storm is a major disturbance of Earth’s magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding Earth. These storms result from variations in the solar wind that produces major changes in the currents, plasmas, and fields in Earth’s magnetosphere.

The solar wind conditions that are effective for creating geomagnetic storms are sustained (for several to many hours) periods of the high-speed solar wind, and most importantly, a southward directed solar wind magnetic field (opposite the direction of Earth’s field) at the dayside of the magnetosphere. This condition is effective for transferring energy from the solar wind into Earth’s magnetosphere.

The disturbance that drives the magnetic storm may be a solar coronal mass ejection (CME) or a co-rotating interaction region (CIR), a high-speed stream of solar wind originating from a coronal hole. The frequency of geomagnetic storms increases and decreases with the sunspot cycle.

During solar maximum, geomagnetic storms occur more often, with the majority driven by CMEs. During solar minimum, storms are mainly driven by CIRs (though CIR storms are more frequent at solar maximum than at minimum).

The increase in solar wind pressure initially compresses the magnetosphere. The solar wind’s magnetic field interacts with the Earth’s magnetic field and transfers an increased energy into the magnetosphere. Both interactions cause an increase in plasma movement through the magnetosphere (driven by increased electric fields inside the magnetosphere) and an increase in electric current in the magnetosphere and ionosphere.

During the main phase of a geomagnetic storm, electric current in the magnetosphere creates a magnetic force that pushes out the boundary between the magnetosphere and the solar wind.

Several space weather phenomena tend to be associated with or are caused by a geomagnetic storm. These include solar energetic particle (SEP) events, geomagnetically induced currents (GIC), ionospheric disturbances that cause radio and radar scintillation, disruption of navigation by magnetic compass and auroral displays at much lower latitudes than normal.

The largest recorded geomagnetic solar storm, the Carrington Event in September 1859, took down parts of the recently created US telegraph network, starting fires and shocking some telegraph operators.

5.Solar particle event (SPE), proton or energetic particle (SEP) storm

A solar particle event or solar proton event (SPE), or prompt proton event, occurs when particles (mostly protons) emitted by the Sun become accelerated either close to the Sun during a flare or in interplanetary space by coronal mass ejection shocks. The events can include other nuclei such as helium ions and HZE ions.

These particles cause multiple effects. They can penetrate the Earth’s magnetic field and cause ionization in the ionosphere. The effect is similar to auroral events, except that protons rather than electrons are involved. Energetic protons are a significant radiation hazard to spacecraft and astronauts.

Real-World Examples Of Space Weather Impacts
  • September 2, 1859, disruption of telegraph service.
  • One of the best-known examples of space weather events is the collapse of the Hydro-Québec power network on March 13, 1989, due to geomagnetically induced currents (GICs). Caused by a transformer failure, this event led to a general blackout that lasted more than 9 hours and affected over 6 million people. The geomagnetic storm causing this event was itself the result of a CME ejected from the sun on March 9, 1989.
  • Today, airlines fly over 7,500 polar routes per year. These routes take aircraft to latitudes where satellite communication cannot be used, and flight crews must rely instead on high-frequency (HF) radio to maintain communication with air traffic control, as required by federal regulation. During certain space weather events, solar energetic particles spiral down geomagnetic field lines in the polar regions, where they increase the density of ionized gas, which in turn affects the propagation of radio waves and can result in radio blackouts. These events can last for several days, during which time aircraft must be diverted to latitudes where satellite communications can be used.
  • No large Solar Energetic Particles events have happened during a manned space mission. However, such a large event happened on August 7, 1972, between the Apollo 16 and Apollo 17 lunar missions. The dose of particles would have hit an astronaut outside of Earth’s protective magnetic field, had this event happened during one of these missions, the effects could have been life-threatening.

There’s more and more interest in the Sun and the space weather it sends our way. As our economy and way of life become more and more reliant on satellites, communications, and power grids, governments and agencies have made understanding and predicting space weather a priority.

There are several spacecraft studying the Sun right now, including SOHO (Solar Heliospheric Observatory), SDO (Solar Dynamics Observatory), and the Parker Solar Probe. These spacecraft are growing our understanding of the Sun, and our ability to predict these dangerous storms.

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