Most surprising to the scientists is why a dramatic shift in the magnetic field that they had modeled and were expecting after the craft left the dominant influence of the Sun’s heliosphere did not occur, even though the plasma density surrounding the craft changed as expected.
Eric Zirnstein, University of Alabama in Huntsville physics graduate student and NASA Earth and Space Science Fellow in Heliophysics, and May UAH doctoral graduate Brian Fayock, who now does data analysis for NASA, are comparing data from different sources with models they have created to try to understand what’s happening.
Imagine a bubble of gas underwater – the surface between the gas bubble and the water corresponds to the heliopause. The heliopause separates regions of different gases. In the case of the Voyager 1 crossing, the heliopause separates material created by the sun from material that surrounds the stars throughout the galaxy. Because the sun is moving through the interstellar medium, it creates a bow wave as well. Outside the heliosphere, there is a 40-fold increase in plasma density.
Read more at: Phys.org