Nasa is planning to launch two sounding rockets into the Northern Lights over Norway to study the movement of particles in a region near the North Pole where the Earth’s magnetic field is directly connected to the solar wind.

The space agency said this winter, when the wind will be low and a day-time aurora will be formed, the two rockets including Caper and Renu will take off.

Both rockets will carry instruments, which will study cusp aurora, a particular subset of the Northern Lights.

In the Northern Lights, energetic particles are said to move fast downward into the atmosphere directly from the solar wind. It continuously streams outwardly from the sun.

Cusp auroras form during daytime only, making it difficult to find. The twin sounding rockets are capable of spotting the cusp aurora even in clouds through ground-based radars.

Dartmouth College in Hanover, New Hampshire CAPER sounding rocket principal investigator Jim LaBelle said: "The magnetic pole is tilted towards North America, putting this magnetic opening, the cusp, at a higher latitude on the European side.

"Both rockets will carry instruments, which will study cusp aurora, a particular subset of the Northern Lights."

"Combine that extra-high latitude with the winter solstice when nights are longest, especially as you go farther north, and you can sometimes see this daytime aurora with the naked eye."

The Cusp Alfven and Plasma Electrodynamics Rocket (Caper) will be launched first and it will followed by Rocket Experiment for Neutral Upwelling (Renu 2). Caper aims to examine the electromagnetic wave that speeds up the electrons downfall into the Earth’s atmosphere or vice versa.

Renu expects to study the relationship between the inflow of electrons that creates the cusp aurora. It will further study electric currents flowing along magnetic field lines and dense columns of heated neutral atoms in the upper atmosphere.

University of New Hampshire in Durham Renu 2 principal investigator Marc Lessard said: "When solar wind electrons collide with atmospheric electrons, they transfer some of their energy, heating the atmospheric electrons.

"The higher heat means the electron populations expand upward along the magnetic field lines."

Image: An aurora is seen over Greenland on April 2, 2011. Photo: courtesy of Nasa / University of Maryland, College Park / Robert Michell.