Solar flares release charged particles that can disrupt the Earth's magnetic field and induce significant electrical currents in power grids, potentially damaging transformers and sensitive equipment.
Solar flares, what are they basically? They are violent explosions that occur on the surface of the Sun, abruptly releasing tons of energy in the form of light and charged particles. These particles, mainly electrons and protons, race through space at high speed, forming what is called the solar wind. Solar flares generally occur near sunspots, dark regions on the surface of the Sun where the magnetic field is particularly intense and turbulent. The more powerful these flares are, the more intense the flow of particles directed towards Earth, which can cause rather strong geomagnetic storms!
The Sun regularly emits large bursts of particles into space, called solar wind. These particles – primarily protons and electrons – rush towards Earth at high speed. Fortunately, our planet is protected by a natural shield: the magnetosphere, formed by Earth's magnetic field. When solar particles reach this shield, they are mostly deflected and glide around the Earth. However, during powerful solar eruptions, some manage to enter through the magnetic poles. This gives rise to spectacular luminous phenomena called northern lights in the north and southern lights in the south. But this beautiful display sometimes conceals a few inconveniences: the massive influx of these particles can seriously disrupt our magnetic field, causing geomagnetic storms. This is where the real troubles begin for our terrestrial electrical networks.
When a geomagnetic storm strikes the Earth, the Earth's magnetic field moves and varies rapidly. These variations generate unwanted electric currents directly in the cables of electrical transmission networks. This is referred to as geomagnetically induced currents (or GIC for short). These unexpected currents then overload electrical transformers, making them less efficient: equipment heats up, ages prematurely, or even deteriorates completely. This can lead to widespread blackouts that sometimes cut off power to entire regions. The larger and more interconnected the network, the more likely it is that a small geomagnetic disturbance will become a big problem. The risk is particularly high in areas near the magnetic poles, such as Canada or Scandinavian countries, where the Earth's magnetic field is most vulnerable to solar fluctuations.
One of the most famous solar eruptions remains the event of March 1989. A massive solar storm caused a widespread power outage in Quebec, plunging nearly 6 million people into darkness for about nine hours. The storm generated uncontrolled electric currents in the grid, frying transformers and equipment.
Looking further back, the event known as Carrington in 1859 remains the star of solar storms: the auroras were visible as far south as Cuba, and telegraph operators literally received electric shocks when touching their equipment!
More recently, in 2003, a series of solar storms disrupted power grids in Sweden and South Africa, resulting in short but still concerning outages. These cases clearly demonstrate that despite advances in technology, our electrical grids remain vulnerable to the whims of the Sun.
To protect electrical networks, backup transformers resistant to surges caused by solar storms are often planned. Operators can also engage in preventive load shedding by temporarily disconnecting certain parts of the grid if a major storm is forecasted. Weather space monitoring systems, such as specialized satellites or ground stations, are also used to anticipate upcoming major storms. The earlier the alerts come, the better we can organize to reduce risks. Engineers sometimes install special lightning protectors or reinforce the grounding of infrastructure to prevent induced currents from causing serious damage.
An extremely intense solar storm could theoretically leave a significant portion of humanity without electricity for weeks or even months, due to disruptions to major electrical transformers.
Astronauts on the International Space Station have special protected areas called 'safe havens' where they retreat during strong solar storms to avoid any danger from energetic particles.
Solar flares and their effects on our atmosphere can also disrupt GPS communications and even reduce the accuracy of common automotive navigation devices for a period of a few hours to a few days.
During intense geomagnetic storms, it may be possible to observe auroras exceptionally far south, sometimes even from Mediterranean countries such as Spain or Italy.
No, not all solar eruptions systematically have a significant impact on electrical grids. Only those accompanied by substantial coronal mass ejections directed towards Earth can induce geomagnetic disturbances that are capable of seriously affecting terrestrial electrical networks.
The physical effects of particles emitted by a solar eruption generally take 18 to 72 hours to reach Earth. However, the electromagnetic pulses from these eruptions reach the planet in just about 8 minutes, at the speed of light.
In general, the Earth's atmosphere and magnetosphere effectively protect humans from the direct effects of particles from solar eruptions. However, these particles can pose risks to astronauts in orbit or on space missions, who are less protected against intense radiation.
The warning signs of a major solar eruption typically include the appearance of large sunspots, a rapid increase in measurable electromagnetic activity, as well as coronal mass ejections detected by specialized solar satellites.
Sure! Here’s the translation: “Yes, several reliable preventive systems exist today. These include continuous monitoring of the sun by satellites, forecasting solar activity by specialized centers, rapid alert systems, and the implementation of protective measures in critical electrical infrastructures.”
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