The Earth has a magnetic field that protects it from radiation from the Sun and deep space. This field is called the magnetic shield. The shield ensures the existence of the biosphere and life on Earth. Planets without a magnetic field are considered dead compared to Earth, even though there may be signs of life.
From time to time, active phenomena occur on the Sun: mass ejections, flares, and shock waves. These phenomena produce energetic particles that fly from the Sun in all directions, including toward the Earth, and enter the magnetosphere. When the shock wave that occurs before the mass ejection collides with the magnetosphere, the Earth's magnetic field begins to disturb, oscillate, and shake. This process is called a magnetic storm.
Magnetic storms are planetary in nature and have a global impact on the Earth and near-Earth space. During a storm, the entire magnetic field of the Earth is disturbed. These disturbances lead to various phenomena. All layers of the Earth's atmosphere, ionosphere, plasmasphere, magnetosphere undergo changes. Flows of energetic particles and currents arise.
What effect do magnetic storms have on the earth's surface?
The induction effect of a magnetic storm is reflected on the surface of the Earth, affecting extended conductive systems: power lines, pipelines, and so on. This can lead to disasters.
One such disaster occurred in March 1989, when transformers in the Canadian province of Quebec, including the capital Ottawa, burned out in the provincial power grid due to electrical currents induced by a magnetic storm. The Earth's atmosphere heated up, swelled, and went up. Low-flying satellites changed orbits and some were lost. Subsequently, they had to be searched for and the constellation had to be rebuilt. A magnetic storm usually lasts from a few hours to a day. In the case of Quebec, the storm lasted nine hours.
Other phenomena that occur due to magnetic storms are auroras. At the poles, the magnetic field enters the Earth as open field lines. The Earth's magnetic shield keeps out energetic particles and protects the Earth by prohibiting particles from moving across the field. But energetic particles can penetrate at the magnetic poles. As they enter the atmosphere, they interact with atoms in the atmosphere and create a colorful glow that we call the polar lights.
Are magnetic storms that dangerous?
The importance of magnetic storms increases over the years due to the sprawl of the Earth's technosphere. Earlier mankind observed only auroras, the most powerful of which was registered in 1859. The English astronomer Richard Carrington observed the most powerful solar flare in the history of observations, which was associated with auroras almost all over the Earth, including the equator. In 1859, the Earth didn't have such an extensive technosphere, satellites, and power lines, so these phenomena weren't felt as clearly. But in 1989, when mankind had already launched satellites and developed extensive power lines and pipelines, the magnetic storm became very significant and greatly affected Quebec's power grid.
The Earth's technosphere is expanding. Many of today's technologies, including GPS, are satellite-based, and satellites are highly susceptible to solar activity. Electronics can fail due to exposure to energetic particles. And the more we implement satellite technology and the longer we make power lines, the more tangible magnetic storms are to the Earth. The induction effect of storms depends on the size of these systems. This suggests that in the design, creation of satellite systems, and expansion of the technosphere we need to take into account factors that were not taken into account before. On the other hand, we need to observe the activity of the Sun and the associated geomagnetic perturbation on the Earth.
How dangerous are magnetic storms to humans?
During a magnetic storm, the environment changes, the atmosphere heats up, and this can lead to changes in pressure in the Earth's atmosphere. These changes, according to medics, can affect the health of people who have a weakened adaptation.
According to statistics, during magnetic storms the number of ambulance calls due to deterioration of the well-being of people with cardiovascular diseases increases by about 20%. At the same time, the magnetic field disturbances themselves, which occur on the Earth, are negligible relative to the field itself. Most often they are about 1/300-1/1000th of the field itself. But the effect is planetary in nature. The human brain has resonances that coincide with the resonances of the ionosphere, about 10 Hz. The human heart also has resonances that coincide with the resonances of the magnetosphere, about 1 Hz. If resonance regions of ionosphere and magnetosphere are excited and electromagnetic radiation density increases in them, it may have an impact on the health of sick people. These interrelations are now actively studied by physicians and biophysicists.
How often do magnetic storms occur?
The Sun's activity experiences an 11-year cycle. This means that from minimum to minimum, from maximum to maximum activity passes about 11 years. Activity maxima can be low and high.. If the cycle maximum is high, the Sun experiences flares and mass ejections.
At the end of November 2003, there was a powerful, active region on the Sun that passed over the Sun's disk for two weeks. It produced a series of flares and mass ejections that led to powerful magnetic storms on Earth and increased geomagnetic activity for an entire week. Such extreme events are rare, about once every 50 years, and can lead to disasters such as the one that occurred in Quebec.
So magnetic storms can be predicted?
At the present stage astronomers are studying the possibilities of space weather forecasting and the entire set of phenomena that occur in the Sun-Earth system. In order to predict the weather, one must have information about the Sun, its active regions, their magnetic configuration, and the possibility of flares and outbursts. If an outburst has already occurred, it travels to Earth for two to three days, depending on speed. During this time, it is possible to understand what kind of outburst it is, in which part of the Sun it occurred, and to predict its effect. As a rule, the right side of the Sun is the most geoeffective.
The magnetic axis of the Earth is tilted with respect to the axis of rotation. In many respects, the effect of magnetic storms depends on the power and velocity of the mass ejection, as well as on the orientation of this axis with respect to the direction of the ejection at the moment of the Earth's collision with the plasma cloud. The magnetic axis is tilted to the axis of rotation by about 11 degrees. It can be facing the Sun or in the opposite direction from the Sun during the collision of the plasma cloud with the Earth's magnetosphere.
Cosmic phenomena are not the same, mass ejections from the Sun occur randomly, they have different amplitude and speed. Therefore, space weather phenomena rarely coincide, they are difficult to predict with high probability. Nevertheless, some predictions are quite feasible. They are now actively used for launching spacecraft and controlling space missions.