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According to the Eureka Alert NASA selects SwRI's PUNCH mission to image beyond the Sun's outer corona:

The four spacecraft will fly in a distributed formation spread around the globe, operating in sync to produce polarized images of the entire inner solar system every few minutes. Each of the four PUNCH spacecraft carries a specialized camera to capture faint glimmers of sunlight reflected by free electrons in interplanetary space.

and also

In addition, the PUNCH satellites will track in 3D the Sun's coronal mass ejections, also known as "CMEs" or "space storms," as they erupt from the corona out into interplanetary space. CMEs cause some "space weather" events that affect Earth, which can threaten astronauts, damage satellites, black out power grids, and disrupt communication and GPS signals.

"Photographing the sky in polarized light is the secret sauce of the mission," DeForest said. "When sunlight bounces off electrons, it becomes polarized. That polarization effect lets us measure how solar wind features move and evolve in three dimensions, instead of just a 2D image plane. PUNCH is the first mission with the sensitivity and polarization capability to routinely track solar wind features in 3D."

Question: Considering that the satellites will all be in LEO, how will they reconstruct a 3D distribution of electrons within a CME near the Sun just by recording faint polarized light? The spacecraft separation of 13,000 kilometers isn't much compared to the 150,000,000 kilometer distance to the Sun. I don't see how a blob can be reconstructed in 3D from such a distance.

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