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Large green aurora and a overlayed screenshot from the mobile app IRF Aurora Alert

Aurora Alert

Table of contents

The auroras are a natural light display that occurs in the polar regions of the Earth. This spectacular phenomenon is the result of interactions between charged particles from the Sun and the Earth’s magnetic field and atmosphere. Simplified it works like this:

Solar wind : The Sun constantly releases charged particles, mostly electrons and protons, in a stream known as the solar wind.

Atmospheric entry :Some of these charged particles manage to enter the Earth’s magnetosphere, particularly around the magnetic poles. Here the particles collide with atoms in the upper atmosphere.

Light emission : When the excited atoms and molecules return to their normal, lower energy states, they release the excess energy in the form of light. The specific colors produced depend on the type of gas and the altitude at which the collisions occur. Oxygen typically produces the common green and red colors, while nitrogen can contribute to purples and blues.

Dancing lights : The rapid movement and swirling patterns of the charged particles in the Earth’s magnetic field create the mesmerizing displays we see as the auroras.

Aurora archive

We have a great tool online if you are interested in browsing auroras from the past

But if you are looking for a high resolution picture from your stay in Kiruna, head over to the allsky image archive

If you are looking for a picture from let’s say October 1 2023, you would:

  1. Choose Year 2023
  2. Then Month 10
  3. Then Day 01
  4. Then Time 21:00

Everything is in a separate folder and the last folder named 21:00 will have 60 pictures in different resolutions for downloading. If you want another timestamp you will have to back up and find the corresponding folder.

IRF Aurora Alert

The IRF Aurora Alert app covers the aurora visible within a circle of approx. 300 km radius around Kiruna.

Terminology

All-sky camera – Also referred to as Firmament camera. It is a camera with a mounted wide angle lens that allows you see east to west, south to north. In other words, the entire sky.

Magnetic field – The magnetic field is an invisible force field generated by moving electric charges, such as those found in the Earth’s core.

Earth’s magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth’s interior out into space, where it interacts with the solar wind (wikipedia)

Excited molecules – When, for example, an electron collides with an Oxygen atom the atom gets excited. After a while it emits a photon (light-quanta). The emitted color (wavelength) of the photon corresponds to the energy of the excited state, or in plain words, this is the source of the auroral light. Electrons colliding with Oxygen atoms produce either red color (6300Å, high altitudes) or green color (5577Å, about 110 km altitude).

The green light (5577Å) is what people most often associate with the aurora. The beautiful purple/blue color (4278Å) that sometimes can be seen is the result of an electron colliding with a Nitrogen molecule. The delay between excitation and photon emission varies and is about 120s for red-line, 0.7s for green line and almost zero for the purple/blue nitrogen emission.)

Time resolution – Time resolution in our case is one minute. It is how often the camera takes a picture. We have other instruments that take up to 100 pictures per second too, but they are using narrow-band interference filters looking at a particular wavelength (color) of the aurora.

Are auroras safe?

Observing the auroras is not only mesmerizing, it is also safe. However, the phenomena associated with the auroras, such as solar flares and coronal mass ejections from the Sun, can have some effects on Earth. Intense solar activity can lead to geomagnetic storms, which, in rare cases, might impact power grids, satellite communications, and navigation systems. This is why we do space weather forecasts at IRF, so that vital infrastructure can take these parameters into consideration when operating.

About us

The Swedish Institute of Space Physics (IRF) is a governmental research institute under the Ministry of Education. IRF conducts basic research and postgraduate education in space physics, space technology and atmospheric physics.

IRF has 60 years of experience in developing instruments for space research projects and participates in several major international collaborative projects using satellites and ground-based equipment.

IRF’s areas of research areas provide knowledge that is necessary for understanding the natural world and the global processes that affect people in their daily lives. IRF contributes, for example, with research into processes in the polar atmosphere through observations and analysis of data focusing on the Arctic and Antarctica.

IRF is an experienced and recognized research institute when it comes to developing instruments to send to planets in the solar system. The data the instruments send back to Earth will give the researchers work for many years to come.

  • The app is developed by Per Danielsson, IRF Lund
  • The camera feed is provided by Dr. Urban Brändström, IRF Kiruna.
  • The algoritm behind the alert system is provided by Dr. Masatoshi Yamauchi, IRF Kiruna