Researchers at Northumbria
are helping increase understanding of the spectacular space phenomenon known as
solar flares and their potential impact on the Earth.
A team of astronomers, led
by Northumbria University PhD researcher Malcolm Druett, have taken a step
forward in understanding a 30-year-old mystery in the formation of solar
flares. The researcher presented the team’s findings on Monday 3 July at the
National Astronomy Meeting in Hull, to coincide with the publication of a paper
in Nature Communications.
Solar flares are large
explosions on the surface of the Sun, associated with the eruption of large
amounts of matter. These coronal mass ejections can cause adverse ‘space
weather’, disrupting communications and even electrical power supplies.
Scientists use a variety of techniques to study the Sun, including looking at
the so-called ‘H-alpha line’ in the solar spectrum, associated with the
hydrogen gas that makes up the bulk of our nearest star. The observed
wavelength of this line changes as a result of the Doppler effect, where light
emitted from gas is slightly bluer if the gas is moving towards us
(blueshifted) and slightly redder if it is moving away from us (redshifted).
For 30 years there has been
a mystery surrounding the H-alpha emission associated with solar flares,
specifically why it is observed from the ground to be strongly redshifted, but
when observed by space probes such as the Solar Dynamics Observatory, it is
seen blue-shifted. Northumbria’s team, led by Malcolm Druett and supervised by
Professor Valentina Zharkova in collaboration with Dr Eamon Scullion, have for
the first time created a model to explain this effect. The approach uses
radiative transfer (transfer of electromagnetic radiation, including visible
light) and hydrodynamic modelling (understanding fluid flow).
Druett and his team found
that short, 10 second injections of super-energetic electrons, so-called solar
energetic particles (SEPs) could be responsible for the redshift in H-alpha and
the formation of solar flares. This will help forecasters predict future adverse
space weather events, allowing agencies on Earth to take protect systems before
it hits.
Professor Zharkova said:
“Solar flares are magnificent energetic phenomena releasing huge amounts of
energy in the form of particles, radiation, coronal mass ejections and
interplanetary shocks into the atmospheres of all the planets, including the
Earth.”
“A greater understanding of
how a solar flare can occur and how much energy they eject into the Sun and
heliosphere is a major priority for the space industry and space weather
forecasts. Our paper sheds significant light on the main factors, which are
able to account for the observations associated with these phenomena both in
the Sun and in the heliosphere.”
The team now hope that the
research will advance the whole field of solar flare dynamics, allowing a
better understanding of the process of flare formation and disruptive space
weather.
Alongside Northumbria’s team, a number of other international
academics collaborated on this discovery. These included Dr Sarah Matthews (Mullard
Space Science Laboratory/University College London) – a specialist in solar
flare investigation, Dr Sergei Zharkov (Department of Physics and Mathematics,
Hull University), a specialist in helioseismology, white light and magnetic
field variations in solar flares and Dr Luc Rouppe Van der Voort (SST developer
and observer) (Institute of Theoretical Astrophysics, University of Oslo,
Norway).
Northumbria is a specialist in the multidisciplinary
research theme Extreme Environments. Academics working in this area explore
research questions in environments where life is under threat from the most
extreme conditions, from the ice of Antarctica to the surface of the Sun. For
more information about research into Extreme Environments click here. Northumbria offers a
range of courses in Mathematics, Physics and Electrical Engineering. To find
out more about studying at the University go to: www.northumbria.ac.uk or
sign up for one of our upcoming Open Days here.
