Breakthrough method for predicting solar storms
Date:
July 29, 2020
Source:
Lund University
Summary:
Extensive power outages and satellite blackouts that affect air
travel and the internet are some of the potential consequences of
massive solar storms. These storms are believed to be caused by the
release of enormous amounts of stored magnetic energy due to changes
in the magnetic field of the sun's outer atmosphere - something that
until now has eluded scientists' direct measurement. Researchers
believe this recent discovery could lead to better 'space weather'
forecasts in the future.
FULL STORY ========================================================================== Extensive power outages and satellite blackouts that affect air travel
and the internet are some of the potential consequences of massive solar storms. These storms are believed to be caused by the release of enormous amounts of stored magnetic energy due to changes in the magnetic field
of the sun's outer atmosphere -- something that until now has eluded scientists' direct measurement. Researchers believe this recent discovery
could lead to better "space weather" forecasts in the future.
==========================================================================
"We are becoming increasingly dependent on space-based systems that are sensitive to space weather. Earth-based networks and the electrical grid
can be severely damaged if there is a large eruption," says Tomas Brage, Professor of Mathematical Physics at Lund University in Sweden.
Solar flares are bursts of radiation and charged particles, and can
cause geomagnetic storms on Earth if they are large enough. Currently, researchers focus on sunspots on the surface of the sun to predict
possible eruptions.
Another and more direct indication of increased solar activity would be
changes in the much weaker magnetic field of the outer solar atmosphere --
the so- called Corona.
However, no direct measurement of the actual magnetic fields of the
Corona has been possible so far.
"If we are able to continuously monitor these fields, we will be
able to develop a method that can be likened to meteorology for space
weather. This would provide vital information for our society which is so dependent on high- tech systems in our everyday lives," says Dr Ran Si, post-doc in this joint effort by Lund and Fudan Universities.
The method involves what could be labelled a quantum-mechanical
interference.
Since basically all information about the sun reaches us through
"light" sent out by ions in its atmosphere, the magnetic fields must be detected by measuring their influence on these ions. But the internal
magnetic fields of ions are enormous -- hundreds or thousands of times
stronger than the fields humans can generate even in their most advanced
labs. Therefore, the weak coronal fields will leave basically no trace,
unless we can rely on this very delicate effect -- the interference
between two "constellations" of the electrons in the ion that are close --
very close -- in energy.
The breakthrough for the research team was to predict and analyze this
"needle in the haystack" in an ion (nine times ionized iron) that is
very common in the corona.
The work is based on state-of-the art calculations performed in the Mathematical Physics division of Lund University and combined with
experiments using a device that could be thought of as being able to
produce and capture small parts of the solar corona -- the Electron Beam
Ion Trap, EBIT, in Professor Roger Hutton's group in Fudan University
in Shanghai.
"That we managed to find a way of measuring the relatively weak magnetic
fields found in the outer layer of the sun is a fantastic breakthrough," concludes Tomas Brage.
========================================================================== Story Source: Materials provided by Lund_University. Note: Content may
be edited for style and length.
========================================================================== Journal Reference:
1. Ran Si, Tomas Brage, Wenxian Li, Jon Grumer, Meichun Li, Roger
Hutton. A
First Spectroscopic Measurement of the Magnetic-field Strength for
an Active Region of the Solar Corona. The Astrophysical Journal,
2020; 898 (2): L34 DOI: 10.3847/2041-8213/aba18c ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2020/07/200729124404.htm
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