Logran mediciones del campo magnético de la corona solar en sus regiones polares / The sun’s magnetic field is where the ‘stuff’ is. It can be dangerous

Por EFE – REDACCIÓN CIENCIA.- El campo magnético de la corona del Sol es el principal impulsor de las tormentas solares y hasta ahora solo se había observado de forma irregular. El uso de nuevos instrumentos ha permitido ver su evolución durante ocho meses y obtener las primeras mediciones de este en las regiones polares.

Un estudio que publica Science indica que, por primera vez, los científicos han realizado mediciones casi diarias del campo magnético coronal global del Sol, lo que proporciona valiosos conocimientos sobre los procesos que impulsan las tormentas solares, que al llegar a la Tierra pueden afectar a tecnologías como el GPS.

La capacidad de comprender cómo el campo magnético acumula energía y entra en erupción se ha visto limitada por la dificultad de observarlo en la corona solar, la atmósfera superior del Sol.

El estudio es un paso adelante en la capacidad para comprender cómo cambia el campo magnético coronal global del Sol de un día para otro, algo fundamental para la capacidad de predecir mejor las tormentas solares y prepararse para ellas.

El equipo, coordinado por el estadounidense Centro Nacional de Investigación Atmosférica, empleó un instrumento llamado Polarímetro Coronal Multicanal Mejorado (UCoMP), publica hoy Science.

El uso combinado de la sismología coronal y las observaciones del UCoMP permitió a los investigadores obtener vistas coherentes y completas del campo magnético de la corona global, la vista de todo el Sol que se obtiene durante un eclipse solar.

UCoMP es principalmente un coronógrafo, un instrumento que utiliza un disco para bloquear la luz del Sol, de forma similar a un eclipse, lo que facilita la observación de la corona.

Durante el estudio, el equipo de investigación produjo 114 mapas de campo magnético entre febrero y octubre de 2022, casi uno cada dos días.

«Estamos entrando en una nueva era de la investigación en física solar en la que podemos medir rutinariamente el campo magnético coronal», dijo Zihao Yang, uno de los firmantes del estudio, en un comunicado.

Las observaciones también produjeron las primeras mediciones del campo magnético coronal en las regiones polares. Los polos del Sol nunca se han observado directamente porque la curva de la estrella cerca de los polos lo mantiene justo fuera de nuestra vista desde la Tierra.

Los investigadores no vieron directamente los polos, pero si realizaron mediciones del magnetismo que emiten, lo que fue posible gracias a la mejor calidad de datos proporcionados por UCoMP, ya que el Sol estaba cerca del máximo solar.

Las emisiones típicamente débiles de la región polar fueron mucho más fuertes, lo que facilitó la obtención de resultados del campo magnético coronal en las regiones polares.

EFE

The sun’s magnetic field is where the ‘stuff’ is. It can be dangerous

BY LAURA BAISAS – For the first time, scientists took nearly daily measurements of this mysterious solar region.

The sun likes to remind us that Earth is merely one part of a joined system. It has ultraviolet rays that can burn our skin and eyes and even drive extinction. Its light can disappear altogether during a solar eclipse and it hurls twisty and tangled solar flares and coronal mass ejections full of plasma at us. Despite our cosmic connection with the sun, there are still numerous scientific mysteries to unravel about this critical star, particularly its magnetic field.

“The sun is not just off in some void of space that we’re not connected to,” Sarah Gibson, a heliophysicist at the National Science Foundation National Center for Atmospheric Research (NCAR) in Colorado, tells Popular Science. “The aurora is actually showing us that direct connection. We’re connected to what’s going on the sun through light, and ultimately, through magnetic fields.”

Now, for the first time, scientists have taken nearly daily measurements of the sun’s coronal magnetic field. This critical spot had only been observed in irregular increments and this new observation offers a more dynamic view of this solar region. With it, we could learn more about what drives intense solar storms that can impact fundamental technologies here on Earth. The findings are detailed in a study published October 3 in the journal Science.

What is the solar magnetic field?

The solar magnetic field is the primary driver of solar storms and flares. As society grows increasingly reliant on technology, this space weather poses threats to power grids, communication systems, and in-space technologies like GPS and satellites.

“We need to understand space weather. We need to predict space weather. The big gap in our knowledge is that we don’t have measurements of the magnetic field in the sun’s atmosphere, its corona,” says Gibson, who is a co-author of this new study. “That’s the part you see during a solar eclipse. The magnetic field controls the shape of that atmosphere, and it controls where the plasma, where the ‘stuff’ is.”

Measuring the magnetism of this region typically requires large, expensive equipment that has only been able to study small parts of the corona. However, a combination of coronal seismology and new observation methods now make it possible for researchers to produce consistent and comprehensive views of the magnetic field of the global corona.

“Global mapping of the coronal magnetic field has been a big missing part in the study of the Sun,” Zihao Yang, a study co-author from Peking University in China and a postdoctoral fellow at NCAR, said in a statement. “This research is helping us fill a crucial gap in our understanding of coronal magnetic fields, which are the source of the energy for storms that can impact Earth.​”

A tale of two instruments

Scientists have been able to routinely measure the magnetic field on the sun’s surface called the photosphere. Measuring the much dimmer coronal magnetic field has been more difficult, limiting a deeper understanding of the three-dimensional structure and evolution of the magnetic field of the corona.

Large telescopes like the NSF’s Daniel K. Inouye Solar Telescope (DKIST) can measure the three-dimensional coronal magnetic fields in depth. With a huge aperture that measures 13-feet in diameter, DKIST is the world’s largest solar telescope. It recently demonstrated its ability for making detailed observations of the coronal magnetic field. However, DKIST can’t map the sun all at once.

To try to get more holistic mapping, the team turned to the Upgraded Coronal Multi-channel Polarimeter (UCoMP). UCoMP is better-suited to give scientists a more global picture of the coronal magnetic field, but in a lower resolution and in a two-dimensional projection.

Like an eclipse, UCoMP can block out parts of the sun. It uses a disc called a coronagraph to enable scientists to measure the sun’s atmosphere. UCoMP has a much smaller aperture compared to DKIST–about 7 inches–but it can take a wider view that makes it possible for scientists to study the entire sun on most days.

The team applied a method called coronal seismology to track magnetohydrodynamic (MHD) transverse waves in the UCoMP data. From the MHD waves, they could create a two-dimensional map of the strength and direction of the coronal magnetic field.

During the UCoMP study, the team produced 114 magnetic field maps between February and October 2022, about one almost every other day.

“We are entering a new era of solar physics research where we can routinely measure the coronal magnetic field,” said Yang.

more in original source https://www.popsci.com/science/space-weather-sun-magnetic-fields