A workforce of researchers used high-resolution observations of the photo voltaic environment and have been in a position, for the primary time, to confirm the existence of one thing known as “Alfvén waves” within the photo voltaic photosphere. Found nearly 50 years in the past by Hannes Alfvén, these waves are actually well-known, however had by no means been detected immediately within the photo voltaic photosphere.
Learning these waves is of nice significance to be taught extra about a number of the most mysterious options of our star, as a result of they’re able to transporting power and data over lengthy distances. It is because the Alfvén waves are strictly magnetic in nature – extra exactly, they’re low frequency magnetohydrodynamics and propagate within the course of the magnetic subject via the oscillation of ions.
As virtually all our bodies – planets, the Photo voltaic System, galaxies and clusters of galaxies – have magnetic fields, figuring out the waves is of nice astrophysical curiosity, and has been more and more the topic of research in numerous contexts, together with interplanetary plasmas. Within the case of the Solar, the waves have been found within the photosphere (see observations, in English, within the video beneath), which is the bottom layer of the photo voltaic environment, and may also help clarify the intense heating of the photo voltaic environment.
The temperature of the photo voltaic corona, the luminous layer of the Solar that we normally see throughout eclipses, is a good thriller. It was solely round 1930 that Grotrian and Edlen found that on this area there may be an emission of iron heated to the purpose that it finally ends up ionized, dropping half of its electrons. Scientists have estimated that with a view to attain such excessive ranges of ionization, temperatures must be round 2 million ° C, nearly 200 occasions the temperature of the photo voltaic floor, and an evidence for these numbers continues to be being sought right this moment.
As for the Alfvén waves, they play a central function in lots of bodily environments, such because the formation of auroras on planets, for instance. They will additionally contribute to the heating and acceleration of ions within the photo voltaic corona, which is why the invention of those waves within the photosphere is so vital. The analysis was led by Dr. Marco Stangalini, from the Italian House Company, and scientists from seven different analysis institutes and universities, utilizing the European House Company’s IBIS imaging instrument.
Along with the observations with IBIS, a part of the workforce carried out numerical simulations (video beneath) to discover the excitation mechanisms of those magnetohydrodynamic waves, which was used to mannequin the dynamics of magnetized fluids – corresponding to these discovered within the photo voltaic environment – to breed the waves that have been noticed within the Solar. In consequence, each observations and simulations pointed to the concrete discovery of Alfvén waves within the star, in response to David Tsiklauri, co-author of the research.
Alfvén waves are transversal and have been deduced in 1942 by Hannes Alfvén via the equations of electromagnetism and hydrodynamics. The experimental affirmation got here seven years later, via the research of waves in liquid mercury. The authors of the brand new research, printed within the journal Nature, hope to make use of the Photo voltaic Orbiter probe and the Photo voltaic Telescope Daniel Okay. Inouye, devoted to the research of the Solar, to proceed researching the function of Alfvén waves in photo voltaic phenomena that stay secret.
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