New Discovery In Earth’s Atmosphere: Solar Wind Energy Transfer

September 12th, 2009

This is going to be a bit technical, and kind of difficult to grasp I would guess, but it is something that is considered quite an important discovery so I want to at least put it out there for people to try and understand. At least describe the finding and what had originally been considered the norm. The discovery isn’t exactly something I want to draw conclusions on since there is so little known about its impacts to make “guesses” as to what it will mean other than it being described by Science Daily as: “could improve the safety and reliability of spacecraft that operate in the upper atmosphere.”

In the Earth’s atmosphere there has always been considered an energy transfer rate that is primarily controlled by the direction of the interplanetary magnetic field. That link will do far better at explaining this process than I ever could.

Now it has been discovered by UCLA atmospheric scientists that there is a previously unknown basic mode of energy transfer from the solar wind to the Earth’s magnetosphere.

“It’s like something else is heating the atmosphere besides the sun. This discovery is like finding it got hotter when the sun went down,” said Larry Lyons, UCLA professor of atmospheric and oceanic sciences and a co-author of the research, which is in press in two companion papers in the Journal of Geophysical Research.

The sun, in addition to emitting radiation, emits a stream of ionized particles called the solar wind that affects the Earth and other planets in the solar system. The solar wind, which carries the particles from the sun’s magnetic field, known as the interplanetary magnetic field, takes about three or four days to reach the Earth. When the charged electrical particles approach the Earth, they carve out a highly magnetized region — the magnetosphere — which surrounds and protects the Earth.

Charged particles carry currents, which cause significant modifications in the Earth’s magnetosphere. This region is where communications spacecraft operate and where the energy releases in space known as substorms wreak havoc on satellites, power grids and communications systems.

The rate at which the solar wind transfers energy to the magnetosphere can vary widely, but what determines the rate of energy transfer is unclear.

“We thought it was known, but we came up with a major surprise,” said Lyons, who conducted the research with Heejeong Kim, an assistant researcher in the UCLA Department of Atmospheric and Oceanic Sciences, and other colleagues.

“This is where everything gets started,” Lyons said. “Any important variations in the magnetosphere occur because there is a transfer of energy from the solar wind to the particles in the magnetosphere. The first critical step is to understand how the energy gets transferred from the solar wind to the magnetosphere.”

It sounds like they won’t be looking for cheap term life insurance anytime soon with this discovery with a little job security.

The discovery was made using equipment that was provided by the National Science Foundation (NSF) at the Poker Flat Research Range in Fairbanks, Alaska. The ground-based radars which send off radio waves that reflect off the ionosphere, allowing scientists to measure the speed at which the ions in the ionosphere are moving.

“The National Science Foundation’s radars have enabled us to make this discovery,” Lyons said. “We could not have done this without them.”