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The Europa Clipper spacecraft, including its instruments, is ready to launch!

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Jupiter’s magnetic field induces a magnetic field at Europa. The mission’s magnetometer investigation will study the moon’s magnetic field. The goal is to reveal Europa’s ocean depth and conductivity, and ice shell thickness.

Jupiter’s magnetic field also carries charged particles called plasma from the volcanic moon Io, Jupiter’s ionosphere, and Europa itself. The plasma distorts Europa’s induced magnetic field and distorts the magnetic signal.

The Plasma Instrument for Magnetic Sounding, or PIMS, will study the density, temperature and flow of plasma near Europa. PIMS will help correct the magnetic induction signal for plasma distortions around Europa. It's the key to precisely determining Europa's ice shell thickness, ocean depth, and conductivity.

How It Works

PIMS has four sensors called Faraday cups to study plasma’s density, temperature, and velocity. Each cup is about three inches (eight centimeters) deep and eight inches (20 centimeters) wide. A grid near the top of each cup produces an electric field to block unwanted particles. In the bottom of each cup is a flat, circular detector plate with three 120-degree segments, like a pie with three equal slices. Plasma creates an electrical current when it strikes the plate, revealing the plasma’s speed and density.

If plasma enters the Faraday cup head-on, it strikes the center of the plate and generates equal currents on all three segments. When plasma enters the cup at an angle, it strikes one segment more than the other two. That tells the instrument what direction the plasma was coming from.

How We'll Use It

Jupiter rotates once every 10 hours, carrying with it a donut-shaped ring of plasma (ions and electrons).

“PIMS measures the characteristics of the plasma in Jupiter's magnetic environment, which is where Europa sits, said Adrienn Luspay-Kuti, principal investigator for PIMS. "One of the beauties of PIMS is that it's a relatively simple instrument. It's a suite of Faraday cups (sensors that will measure plasmas, or electrically charged gases). The measurements will enable us to decipher complex physical processes that ultimately will help us understand the properties of Europa's subsurface ocean.”

“Europa creates a magnetic field in response to an external magnetic field that comes from Jupiter, Luspay-Kuti added. "Measuring that magnetic field can tell us a lot about Europa’s subsurface ocean. The problem is that there's also plasma in the magnetosphere of Jupiter and that plasma hits Europa. Europa basically sits in this plasma river. We need to know how to subtract that plasma, and that's what PIMS will help with.”

“Plasma distorts magnetic fields around Europa and obscures the induction signal from the magnetometer,” said Corey Cochrane, a JPL engineer and investigation scientist on the ECM and PIMS teams. “PIMS will allow us to model the plasma and subtract its contribution from magnetometer data.” It will let scientists study Europa’s ocean depth and conductivity, and ice shell thickness.

Meet the Team

“It’s totally fun to be a part of this thing. It’s definitely a dream job.”