Early forecasting of geomagnetic storms gives us time to prepare

Early forecasting of geomagnetic storms gives us time to prepare

Coronal hole on the Sun SDO/AIA.

Scientists at the Skolkovo Institute of Science and Technology (Russia), together with colleagues from the Leibniz Institute for Astrophysics (Germany), the University of Graz and Kanzelhohe Observatory (Austria), the University of Zagreb and the Zagreb Astronomical Observatory (Croatia) developed a method for predicting geomagnetic storms directly from solar observations .

The findings make it possible to increase lead warning times from hours to days and protect the operation of engineering systems in space and on Earth from the influence of space weather. The study has been published in Monthly Notices of the Royal Astronomical Society.

the solar wind, a stream of electrons, protons, and helium nuclei, blasts permanently from the Sun, flooding the Earth and all the planets of the solar system. The high-speed solar wind currents originate from coronal holes in the Sun – dark regions of low-density plasma in the solar corona, with magnetic field lines Opening up freely in interplanetary space, ionized atoms and electrons escape into interplanetary space, leaving a “hole” in the corona.

When the fast solar wind catches up with the slower, more intense solar wind, which is generated by the “quiet” part of the solar corona, leads to the formation of a giant structure called the formation interaction zone, which rotates with the sun. It could reach Earth’s orbit in a few days geomagnetic storms and twilight. and since then Coronal perforation They can reappear before us in one solar cycle, and the fast solar winds from the coronal hole can cause frequent geomagnetic storms and aurorae, which recur every 27 days.

The propagation time of the solar wind from the Sun to Earth is approximately one to five days, creating a natural early warning lag. However, the magnetic composition of the interplanetary turbulence, in particular the southern component of the interplanetary magnetic field, which is driving the storm, cannot be determined at present from Solar noteswhich severely limits the possibility of forecasting a storm several days in advance.

Current approaches to forecasting geomagnetic storms are mainly limited to a short-range forecast with a lead time of hours, based on measurements of the solar wind and the interplanetary magnetic field at the near-Earth L1 Lagrangian point.

An international group of scientists has addressed a very important question for space weather applications—whether geomagnetic storms caused by currents of the high-speed solar wind can be predicted directly from solar observations—and presented a new, successful effort to predict geomagnetic storms using information from coronal holes in the Sun.

The results allow forecast lead times to be extended from hours to days, which is critically important for warnings of space weather conditions in the near-Earth environment and other space weather applications.

“We have empirically established relationships between the regions of coronal holes on the Sun that are derived from them satellite images and solar wind speed at L1; between remote sensing magnetic field maps of the solar photosphere and in situ measurements at L1; as well as between coronal hole regions, the corresponding magnetic field in the Sun, and geomagnetic indices,” says the first author of the study, Simona Nitti, MSc Scholtech graduate who is currently pursuing her PhD studies at the University of Leicester in the UK.

“We have shown that the magnetic field from a coronal hole propagating from the Sun to the Earth is conserved in more than 80% of cases. This opens up the possibility of using the magnetic field derived from solar observations instead in L1. In addition, to improve predictions, we have included in the prediction model Geomagnetic activity reflects seasonal changes in the southern component of the interplanetary magnetic field.

“Our study represents a major step in modeling geomagnetic activity and in interpreting the observed differences in indices of geomagnetic activity. We considered the southbound interplanetary magnetic field (IMF) to be an important driver of geomagnetic activity. Such a component magnetic field, BS, when separated by a polarity box IMF, showing a pair of glasses pattern: When the IMF points towards/away from the Sun, the field is enhanced in spring/autumn and decreased in fall/spring.We incorporated this model into our prediction model.Since we used information about coronal holes And for each coronal hole of a particular polarity, it was necessary to use the appropriate pattern of B for a particular polarity, says Dr. Mario Bandić, co-author of the paper.

In this way, we broke with the common practice of interpreting variations that appear in geomagnetic indices as the ‘Russell-McPherron effect’ and considered B-shapes separated by the polarity revealed by the satellite data. Polarity fields from the Russell-McPherron model for half-term undefined Bs: For For the IMF pointing to the sun, the point B is zero in the fall, and for the IMF the point away from the sun Bs is zero in the spring. Taking the realistic shapes of the polar fields as input enabled us to obtain a highly accurate and reliable prediction model.”

“The strength of the geomagnetic storm is determined by the characteristics of the solar wind as well as by the ‘frozen’ solar energy.” magnetic field Blown by the solar wind interplanetary space. However, the solar wind, like any wind, is volatile and unstable, which makes it difficult to predict its characteristics,” says Tatyana Podladchikova, associate professor at the Skoltech Center for Digital Engineering and a co-author on the paper.

“Our approach based on using information from solar coronal holes opens a new chapter in forecasting geomagnetic storms directly from solar observations extending forecast periods from hours to days, which is of paramount importance for the protection of space and terrestrial infrastructures and the advancement of space exploration. Whatever storms may be Speaking, we wish everyone good weather in space.”

more information:
Simona Nitti et al, Prediction of Geomagnetic Storms from Solar Coronal Holes, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stac3533

the quote: Early Prediction of Geomagnetic Storms Gives Us Time to Prepare (2023, January 24) Retrieved January 25, 2023 from https://phys.org/news/2023-01-earlier-geomagnetic-storm.html

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