Observations of the Outer Heliosphere, Heliosheath, and Interstellar Medium

Area of Science:

• Space physics
• Heliophysics
• Plasma physics

Background:

• The heliosphere is the vast bubble of solar wind and magnetic fields surrounding our solar system.
• Understanding the heliosphere's boundary is crucial for comprehending our solar system's interaction with interstellar space.

Purpose of the Study:

• To review the first direct observations from spacecraft that have entered the interstellar medium.
• To summarize findings on the solar wind plasma and magnetic fields throughout the heliosphere and beyond.

Main Methods:

• Analysis of data from the Voyager 1 and 2 spacecraft.
• Review of observations from the New Horizons spacecraft in the outer heliosphere.
• Compilation of solar wind plasma and magnetic field measurements.

Main Results:

• Voyager spacecraft have successfully crossed the heliopause into the interstellar medium.
• First in-situ measurements of the termination shock, heliosheath, and heliopause have been obtained.
• New Horizons is providing new data on solar wind and pickup ions in the outer heliosphere.

Conclusions:

• Spacecraft are providing unprecedented insights into the heliosphere's boundary and the interstellar environment.
• Direct observations confirm and refine models of the heliosphere's structure and interaction with interstellar space.
• Future research will continue to analyze this unique data to understand space weather and cosmic ray modulation.