Back in junior high science, most of us learned that a magnetic field can induce electrical current. And that conversely, electric current creates a magnetic field.
That happens in small ways all over the world and it also happens in big ways. The earth itself has electricity running within it, which produces a global magnetic field. This field surrounds the planet, and can be measured by instruments called magnetometers. In fact there’s one buried in the ground at Northern Lakes College in Slave Lake.
“We’re measuring the earth’s magnetic field,” says Athabasca University space sciences researcher Dr. Martin Connors. “But mostly we’re interested in changes in the field when there’s an aurora.”
That’s the aurora borealis, more popularly known as the northern lights. When it’s pulsating up there in the night sky above Slave Lake, it means there’s more than the usual amount of electric current running around in the magnetosphere, to put it unscientifically.
“It’s like a light tube,” says Connors. “Gas with electricity passing through it.”
The lights in the sky are one effect. Another is the change the aurora sometimes induces in the earth’s magnetic field.
“When the magnetic field changes rapidly it creates another electrical current on the surface of the earth,” Connors explains. “And that can do damage.”
For example, in Quebec the power grid was taken down by such magnetic activity. That’s less of a risk in Alberta, Connors says, but there are other economic considerations.
“Electrical currents on earth can cause pipeline corrosion,” he says.
The trick is learning how to predict when the aurora is likely to occur, so as to mitigate the effects of the rogue electrical current it induces. But so far, scientists haven’t figured out how to make reliable predictions, and that’s why Connors was in Slave Lake last week, installing his magnetometer in the rain.
Together with his colleague Dr. Ian Shelton and Northern Lakes College science instructor Rob Irwin, Connors buried his instrument on the college grounds. It needs to be well away from any metal objects, he says, because they all have magnetic fields.
Connors also has one at a college campus in Paddle Prairie, but its location is not ideal.
“If you move a metal chair, it drives it completely nuts,” he says.
The one at Slave Lake isn’t near any metal, but it is connected to a computer in Irwin’s lab that constantly records the data coming in. Connors can keep tabs on the data from Athabasca, where a similar sensor is pumping out the same type of info.
When the northern lights are humming and the earth’s magnetic field responds, the magnetometer will pick it up. Added to photographs of the night sky from below and above (from a satellite), it will make a nice package of data for scientists like Connors to study.
As it happens, others are interested in the same science. Connors says a Japanese aurora project has been doing similar work in northern Saskatchewan for several years.
The magnetometer started out in a military application during World War II. Submarines used it to detect ships passing overhead. It works by means of three coils picking up magnetic ‘signatures’ from three different directions.
The magnetic field, naturally, produces electric current in the coils. The strength of the current implies the strength of the field.
Another use for magnetometers is in diamond exploration. For the past few years Ashton Mining has been doing magnetic surveys by helicopter in the Buffalo Hills north of Red Earth Creek. The device they use is similar to the one at the college, in that it reads the earth’s magnetic field. Anomalies in that field suggest the presence of deposits of ore.
Directional drilling for ore could benefit from the work Connors is doing. He says the drilling relies on magnetic impulses from ore deposits to know where to go. Disturbances in the field caused by the aurora could mess up the process. So being able to predict such atmospheric agitation would be good.
Connors thinks it can happen.
“If we could get to the same stage we’re at with weather (prediction), we’d be pretty happy.”

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