The effects of solar activity on communications technology. Interview with Sophie Murray, AXA Ph.D. fellow at the School of Physics, Trinity College Dublin (Ireland).
Could you briefly describe the goals of your research
I study the physics of the Sun, specifically looking at
sunspots and solar flares. My research topic is ’Understanding the complex
magnetic topologies of solar active regions’. Basically what this means is that
I am hoping to better predict solar flares by looking at the magnetic fields of
sunspots. I use data from satellites that observe the Sun to look at how the
magnetic field changes over time before a flare occurs and then how it is
changed by the flare. This has implications on Earth due to space weather,
which can disrupt communications and electronics both on the ground and on satellites.
What is “space weather”?
Space weather describes the interaction of magnetic fields
and particles, which have been ejected from the Sun, with the Earth’s upper atmosphere
and surrounding magnetic field. The particles form what is known as the solar wind.
As the solar wind travels through the solar system, the Earth’s magnetic field
acts as an obstacle and deflects the particles around the planet, rather than
bombarding the atmosphere or surface.
Space weather has a number of effects on the space
surrounding the Earth; the most re cognisable might be the aurorae, also called
the ’Northern Lights’. Sometimes not all the par ticles are deflected and they
launch downwards into our atmosphere at the polar regions where they interact,
resulting in emissions that give the aurora’s multicoloured glowing appearance in
the skies. In periods of higher activity on the Sun, many more solar flares
occur than normal, increasing the amount of particles and radio emissions ejected
from the Sun. This increased activity can cause geomagnetic storms, which are
formed when the solar flare causes the solar wind to hit the Earth’s magnetic
field much more strongly, causing a temporary disturbance in the upper atmosphere.
This can cause severe disruptions to communications and power grids across the
globe. The increased activity can also cause aurorae to form in even lower
latitudes, as far down as the equator in very strong events.
What are the impacts of space weather on aviation and space
In terms of aviation, flight crews, passengers and on board
electronics are all under direct exposure to space weather on transpolar flights.
Here, they are exposed to higher levels of radiation, which increases during
periods of high solar activity. Too much exposure can cause illness so flight
crews must limit the number of flights they make yearly. Radio communications
between pilots and the ground can also be affected, causing diverted flights if
a storm occurs. The more accurately we can predict these storms, the better for
the airlines operating these routes. Astronauts’ lives can be threatened due to
the high dosages of solar radiation they are exposed to and to the energetic
particles from the Sun bombarding the space shuttle. The spacecraft shielding
and protection from their spacesuits must be sufficient or an increased dose of
radiation and particles due to a solar flare could be lethal. Solar activity
monitoring systems are imperative to keep the astronauts safe.
Why does solar activity affect human technologies such as
GPS, satellites, or weather monitoring?
The particles accelerated during solar flares can damage and
degrade electronics on board spacecraft. For example, microchips can be damaged,
causing errors in software commands. Geomagnetic storms can also blind sensors
on board the craft and interfere with electronics. Sufficient shielding for
instruments on board satellites is necessary to prevent degradation and is an
area of continuous research to improve the materials used. The signal
propagation of GPS and other satellite navigational systems are also affected
in a similar fashion, as well as the disruption to the electronics on board the
satellites. The impact of this on the ground could be wide-spread, disrupting
shortwave radio broadcasts, mobile phone networks and transport navigation systems.
What are the long-term perspectives on that topic?
In order to minimise the impact of space weather on our
technologies, a solar activity-forecasting infrastructure must be developed
between governmental and commercial sectors. But first, we as scientists must
understand the fundamental physical processes involved in driving space
weather, such as sunspot magnetic fields. The more we know about these processes,
the more we can improve statistical models to predict when a flare will occur. The
accuracy of prediction methods available presently needs to be increased, in
order to be able to predict solar activity over shorter time scales of hours
rather than days. Scientists do need as near-real time solar data as possible for
space weather predictions. ■
Sunspots are regions on the
surface of the Sun that appear as dark spots and have very strong
magnetic field. Solar flares are a very releases of large amounts of
energy, which is stored in the solar atmosphere. The flares can hurtle
towards Earth in the form of very energetic particles, X-rays,
ultraviolet and radio emissions, amongst others.
Image 1 : Crédit photo NASA/courtesy of nasaimages.org
Image of the sun taken by the NASA “SOHO” spacecraft in 2003.
Image 2 :
Collection of images depicting the Sun’s impact on Earth: starting with
a solar flare eruption on the Sun on the left, causing changes in the
Earth’s atmosphere in the centre leading to the occurrence of the aurora
in Alaska in the image on the right.
Murray is a AXA PhD fellow at the School
of Physics, Trinity College Dublin (Ireland).
Click here to find out more about this research supported by the AXA Research Fund