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- Ray of Light: will physicists be able to change our understanding of solar storms
Ray of Light: will physicists be able to change our understanding of solar storms
A new study by an international team of scientists has called into question one of the established ideas about space weather. It turned out that high-energy cosmic rays can react to the magnetic structures of solar storms, although previously it was considered impossible. The authors of the work believe that the discovery can become the basis for new methods of studying solar activity and clarifying space weather forecasts. However, Russian scientists believe that it is premature to talk about its practical value. For more information on how the discovery may affect the study of the relationship between the Sun and the Earth, see the Izvestia article.
What is the essence of the discovery
Scientists have discovered a new way to observe solar storms — using high-energy cosmic rays that come to Earth from the depths of the Galaxy. The results of a study published in the journal Physical Review Letters have shown that even particles with energy in the teraelectronvolt range can carry information about the structure of magnetic fields inside solar emissions. This came as a surprise to experts, since it was previously believed that such energetic particles practically do not respond to disturbances occurring in the vicinity of the Sun.
To understand the significance of the discovery, it is important to understand how the space around our star is arranged. As Anatoly Petrukovich, director of the Space Research Institute of the Russian Academy of Sciences, explained, interplanetary space is not an empty space at all. It is filled with plasma and a magnetic field, which are continuously ejected by the Sun and form the solar wind. The Earth is constantly inside this stream, and after flares, dense clouds of plasma and magnetic field pass through the Solar System, capable of causing magnetic storms.
— Against this background, galactic cosmic rays are continuously coming to Earth — high-energy particles that are born far beyond the Solar System. Before reaching our planet, they pass through a magnetic environment formed by the solar wind. As a result, a kind of "magnetic bubble" appears around the Sun, which affects the propagation of cosmic rays, deflecting them, the expert explains.
As the scientist noted, the connection between solar activity and the flow of cosmic rays has been known for a long time. The more active the Sun is, the stronger the magnetic field surrounding it becomes and the more effectively it prevents the penetration of galactic particles into the inner regions of the Solar system. Therefore, the decrease in the cosmic ray flux has been used for many decades as one of the indirect indicators of solar activity.
However, a new study has shown that this relationship may be much more complex than previously thought. An international team of scientists analyzed data from the Chinese observatory LHAASO, the world's largest complex for recording cosmic rays. Researchers studied the solar storm that occurred in November 2021 and found an unusual effect: for several hours, high-energy cosmic rays came to Earth unevenly, with noticeably fewer recorded from one direction than from the other.
Previously, it was assumed that particles of such energies should pass almost unhindered through the magnetic structures of solar storms. Nevertheless, observations have shown the opposite. The authors concluded that magnetic turbulence at the leading edge of the solar plasma ejection is capable of scattering some of the cosmic rays and creating a measurable imbalance in their distribution along the directions.
How a new discovery will help to better predict solar storms
Today, forecasting solar storms is based primarily on observations of the Sun itself. Astronomers record flares and coronal mass ejections using spacecraft and ground-based telescopes, after which they estimate the speed of movement of the plasma cloud and the probability of its meeting with the Earth. Sergey Petrov, Head of the Department of Astronomy at St. Petersburg State University, noted in an interview with Izvestia that this approach remains the most effective.
"Optical and radio observations of solar flares and coronal mass ejections are certainly the most reliable and long—term forecast of the impact of solar activity on space weather, simply because electromagnetic radiation takes only eight minutes to reach the Earth's surroundings, and solar wind particles take from a day to three," explains the scientist.
According to him, observatories like China's LHAASO play an important role in studying cosmic rays. However, there is no reason to say that they will be able to replace existing solar activity monitoring systems.
Anatoly Petrukovich shares a similar assessment. He emphasizes that it is important to distinguish between predicting the solar flare itself and clarifying the parameters of an event that has already occurred.
— Changes in the cosmic ray flux cannot be used as a precursor to a solar flare. If such changes are registered, it means that the solar event has already occurred. Therefore, the maximum that the new method is potentially capable of is to help more accurately determine the time of arrival of the disturbance to the Earth," the expert adds.
At the same time, the scientist notes, today experts already have quite effective means of observation. Spacecraft allow you to see the moment of the plasma release, track its movement through interplanetary space and record the cloud's approach to Earth. Therefore, there is no reason to claim that the new approach will be able to significantly improve the accuracy of existing forecasts.
Another issue that the researchers will have to solve is to understand the physical nature of the discovered effect. So far, scientists have recorded only a statistical relationship between a solar storm and a change in the flow of high-energy cosmic rays, but the mechanism itself remains the subject of discussion.
— Direct interaction of the solar wind with particles of such high energies seems unlikely, as the authors themselves admit. One of the possible explanations is the processes occurring in the Earth's atmosphere, where effects associated with both solar activity and cosmic rays can also occur," explains Sergey Petrov.
However, even if it turns out later that the discovered mechanism works differently than the authors of the article assume, the study itself remains important, Petrov believes. It opens up a new direction for studying the relationship between solar activity, cosmic rays, and processes in near-Earth space.
Why accurate flare prediction is important for humans
Modern civilization is increasingly dependent on space infrastructure, so the effects of solar activity today can be felt far beyond scientific laboratories.
According to Anatoly Petrukovich, it is more correct to talk not about "solar storms", but about various manifestations of solar activity — primarily solar flares and related plasma emissions. They cause most of the dangerous effects that satellite systems and ground infrastructure face.
— One of the first consequences is the warming of the upper atmosphere layers under the influence of increased solar radiation, including ultraviolet radiation. Because of this, the atmosphere expands, and its resistance to spacecraft in low orbits increases. As a result, the satellites begin to lose altitude faster, and it becomes more difficult to predict their movement," the expert clarifies.
Additional problems arise when tracking space debris. As Petrukovich explained, due to changes in the density of the upper atmosphere, its orbits begin to differ markedly from the calculated ones, which reduces the accuracy of forecasts and increases the complexity of ensuring the safety of space flights.
No less dangerous are solar cosmic rays, high—energy protons that occur directly during solar flares. Unlike the galactic cosmic rays discussed in the new study, they are born on the Sun itself and can pose a serious threat to spacecraft and crews of manned missions. In addition, during magnetic storms, due to disturbances in the upper atmosphere of the Earth, the ionosphere, the quality of radio communication deteriorates.
History shows that the effects of strong solar activity can affect a wide variety of areas of life. According to Sergey Petrov, a well-known example is the magnetic storm of 1859, the so-called Carrington event. Then the telegraph operators received electric shocks, and some communication lines continued to work even after the power supply was turned off due to induced currents.
— In the 20th century, the impact of space weather has become even more noticeable. So, in May 1967, a solar flare disabled American long-range radars. Because of this, there was a risk of mistaking the interference for the beginning of a military attack, and only timely intervention by specialists made it possible to avoid a dangerous escalation. After that, the US Department of Defense created its own space weather service," the expert continues.
Other examples also clearly demonstrate the scale of the possible consequences. In August 1972, a magnetic storm led to the spontaneous detonation of American naval mines in the South China Sea. In March 1989, a powerful geomagnetic disturbance left almost the entire Canadian city of Quebec without electricity for about nine hours, and also caused serious computer failures. And more recently, in February 2022, increased solar activity led to the loss of 40 recently launched Starlink satellites, which could not reach their calculated orbits and burned up in the atmosphere.
That's why scientists continue to look for ways to make space weather forecasts more accurate. Even if additional information buys only a few hours, it may be enough to adjust satellite operating modes, prepare energy companies for possible geomagnetic disturbances, or warn communications system operators in advance.
What role does Russia play in space weather research?
Finding new ways to study solar activity is a task in which Russia already occupies a prominent place today. Anatoly Petrukovich emphasizes that a strong scientific school in the field of space weather has been formed in the country.
According to him, ground-based solar telescopes are constantly operating in Russia, which monitor the state of the Sun and near-Earth space. In addition, four Ionosphere satellites have recently been launched, designed to monitor solar activity and its effects on the upper layers of the Earth's atmosphere, ionosphere and radio communications.
— Observations of cosmic rays play an equally important role. A network of neutron monitors is currently operating, with stations located, in particular, in Troitsk, on the Kola Peninsula and in other regions of the country. These installations continuously record changes in cosmic ray fluxes and make it possible to detect signs that a plasma cloud is approaching the Earth after a solar flare. However, such observations do not allow us to predict the outbreak itself, they help to track the processes that have already begun and clarify the parameters of their development," the expert explains.
In addition to the network of neutron monitors, Russia has a number of large scientific complexes that study the Sun and cosmic rays. Among them, Sergey Petrov notes the telescopes and coronographs of the Kislovodsk station of the Pulkovo Observatory, the instruments of the National Heliogeophysical Complex of the Russian Academy of Sciences, the Baikal Astrophysical Observatory, the Siberian Solar Radio Telescope, as well as the Tunka Complex, which is one of the most modern Russian installations for studying cosmic rays and gamma-ray astronomy.
At the same time, the importance of such research goes far beyond improving space weather forecasts. According to the Izvestia interlocutor, today scientists still face many fundamental questions about how exactly the Sun, the interplanetary medium and the Earth interact.
Переведено сервисом «Яндекс Переводчик»
