Radio emission from the heliopause triggered by an interplanetary shock

Area of Science:

• Space Physics
• Heliophysics
• Plasma Physics

Background:

• Voyager 1 and 2 detected unusual radio emissions between 2-3 kHz.
• The event began in July 1992, originating near the heliopause.

Purpose of the Study:

• To analyze the heliospheric radio emission event.
• To determine the origin and characteristics of the interplanetary shock.
• To estimate the distance to the heliopause.

Main Methods:

• Analysis of radio emission data from Voyager 1 and 2.
• Modeling of interplanetary shock propagation and effects.
• Correlation of shock effects across multiple spacecraft (Pioneers 10 & 11, Voyagers 1 & 2).

Main Results:

• A strong heliospheric radio emission event was observed.
• The event was linked to an interplanetary shock from May-June 1991 solar activity.
• Shock propagation speed was estimated at 600-800 km/s.
• The heliopause distance was estimated to be between 116 and 177 AU.

Conclusions:

• The heliospheric radio emission provides evidence of shock interaction at the heliopause.
• The study offers a new method for estimating heliopause distance.
• Understanding heliospheric shocks is crucial for outer heliosphere research.