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Methods and systems for imaging bulk motional velocities in plasmas

Stage: Development

The method and apparatus for imaging the distribution of bulk motional velocities in plasmas such as inertial confinement fusion (ICF) implosions use multiple narrow-band x-ray crystal imaging systems, one or more of which have a bandpass tuned to lie within the Doppler-broadened emission line profile of a suitable plasma emission line. Crystals tuned on the one end of the profile will preferentially reflect x-rays from plasma ions moving towards the crystals, while crystals tuned to another end of the profile will preferentially reflect x-rays from plasma ions moving away from the crystals.



A plasma is one of the four fundamental states of matter, the others being solid, liquid, and gas. Plasma behavior may be extraordinarily varied and subtle. In particular, hydrodynamic motion in imploding plasmas is not well diagnosed at all relevant spatial scales. It has been theorized that bulk macroscopic motion can be imparted to regions of imploding plasmas by three-dimensional (3-D) effects, serving as a sink for energy that would otherwise go towards heating the plasma. However, there has been no ability to directly diagnose such motion.

To overcome this diagnostic incapability, we developed plasma analysis using Doppler shift principles. We developed a novel method and apparatus for imaging the distribution of bulk motional velocities in plasmas such as ICF implosions. The innovation uses multiple narrow-band x-ray crystal imaging systems, one or more of which have a bandpass tuned to lie within the Doppler-broadened emission line profile of a suitable plasma emission line. Crystals tuned on the one end of the profile will preferentially reflect x-rays from plasma ions moving toward the crystals, while crystals tuned to another end of the profile will preferentially reflect x-rays from plasma ions moving away from the crystals. Software analysis produces images that have or show a color-coded map of bulk motional velocities. This is an important measurement capability that could have an enormous impact on ICF progress at facilities such as the National Ignition Facility. Other applications include high energy density physics and test facilities.

The method can process simulated data from a realistic (3-D) simulation of an implosion plasma. Refinement of the design parameters to adjust various factors may also occur, such as the crystal or aperture dimensions, without departing from the scope of the innovation. In addition, the method and apparatus may be configured for use with backlit absorption imaging of cold plasmas, such as but not limited to explosive-driven implosions.


Applications and Industries

  • Plasma analysis
  • Inertial confinement fusion
  • High energy density physics

Benefits

  • Enable unique measurements of plasma properties
  • Diagnostic measurements of inertial confinement fusion plasmas

Patents