Luminescence from Collapsing Centimeter Bubbles Expanded by Chemical Reaction

Area of Science:

• Physics
• Chemical Engineering
• Materials Science

Background:

• Inertial confinement fusion aims to achieve high temperatures and densities for energy generation.
• Achieving strong inertial confinement of gases in liquids presents significant challenges due to instability and energy loss.
• Previous methods have struggled to reach the extreme conditions necessary for studying collapse dynamics.

Purpose of the Study:

• To introduce a new method for achieving exceptionally strong inertial confinement of a gas within a liquid medium.
• To investigate the dynamics and conditions during the collapse of a chemically reactive bubble.
• To explore the development of inertial instabilities during bubble collapse at extreme temperatures.

Main Methods:

• A centimetric spherical bubble filled with a reactive gaseous mixture was expanded via an exothermic chemical reaction.
• The reaction products condensed at the bubble wall, creating a nearly empty cavity.
• Cavity radius dynamics and spectroscopic measurements were used to infer temperatures and study collapse events.

Main Results:

• Temperatures exceeding 20,000 K were reached at maximum compression.
• The method demonstrated strong inertial confinement, with the cavity becoming essentially empty upon collapse.
• Unique space and time-resolved sequences of collapse events were captured, including the development of inertial instability.

Conclusions:

• The reported method offers a novel approach to achieving extreme conditions through gas confinement in liquids.
• The high temperatures and detailed observation of collapse dynamics provide valuable data for fundamental physics research.
• Understanding inertial instabilities during collapse is crucial for advancing inertial confinement technologies.