Giant interplanetary shock waves are reflected in our solar system, emanating from the sun and bursts of charged particles or solar winds escaping it. But measuring such a shock in detail takes some very finely tuned instruments – and scientists just managed it for the first time.
These shocks are made up of particles that transmit energy through electromagnetic waves rather than bouncing directly into one another – this is known as a collision-free impact.
Understanding how these shocks occur near the Earth can be helpful on a larger scale, as these types of shockwaves also derive from things like supernovae and even black holes.
The solar winds that cause interplanetary shocks are of two types: fast and slow (as you might guess, one of the key differences between them is their travel speed). While rapid flow outstrips slow flow, a wave is created that causes ripples to propagate in the solar system.
Thanks to NASA's Magnetospheric MultiScale Satellites (MMS), we were already able to capture the shockwave as it propagates into space – because the four satellites that make up the MMS were only about 20 kilometers or 12 miles apart, close enough for detect interplanetary shock waves while flashing for only half a second.
"The [MMS] the spacecraft received unprecedented multi-point measurements of particles and high-resolution interplanetary shock fields, "the researchers wrote in their paper.
In particular, MMS-based Plasma On-Line Instruments are responsible for making all the important readings – a set of devices capable of measuring ions and electrons in space up to six times per second.
The instrument detected two clumps of ions: one from the very wave of solar wind and one pushed out of the way when the wave passed.
The team says this helps explain how energy and acceleration are transmitted as these shocks travel; due to the relatively small scale of the MMS area, it also managed to pick up small irregularities within the shock.
Most shockwave measurements should be within MMS capabilities, says the team behind the latest research – not only strong interplanetary shocks, but also weaker and rarer ones that scientists know less about. .
And this is just the latest pen in the MMS cap: it is already responsible for analyzing how energy is dissipated when solar storms strike the earth's atmosphere, and for recording other key changes in our magnetosphere.
Ultimately, these interplanetary shock waves contribute to space time, which can have a dramatic impact on our own planet – which is why scientists are so eager to learn more about them, not only to make new discoveries, but to refine existing hypotheses. With MMS, they already have their first close-up look.
"Study [interplanetary] shocks in kinetic scales thus offer new test beds for our current understanding, "the researchers say.
The study was published in Geophysical Research Journal,