Measurements of Hypervelocity Plasma Jets for Plasma Liner-Driven Magneto-Inertial Fusion
Event details
| Date | 13.09.2012 |
| Hour | 14:30 › 15:30 |
| Speaker | Prof. M. Gilmore, University of New Mexico, Albuquerque, New Mexico, USA |
| Location |
PPB 019
|
| Category | Conferences - Seminars |
Magneto-inertial fusion (MIF) refers to several different schemes to produce fusion energy with densities and confinement times intermediate between magnetic confinement fusion and inertial confinement fusion (ICF). MIF seeks to utilize magnetic fields to reduce transport such that implosion times required for ICF can be reduced from ~ nanoseconds to ~ microseconds, thereby reducing enormously the complexity and cost of the implosion driver (laser or pulsed power system). Several different MIF schemes are now being pursued using both mm-scale and cm-scale targets, including magnetized (via external coils) laser direct drive targets at U. Rochester, USA, MAGLIF (MAGnetic Liner Inertial Fusion) at Sandia National Laboratories, USA, and magnetized target fusion (MTF) at the Air Force Research Lab and Los Alamos National Laboratory (LANL), USA.
In the MTF (magnetized target fusion) scheme, a cm-scale compact toroid (CT) with density n ~ 10^22 m^-3, temperature T ~ 100 eV is formed and translated in ~ 10 μs via pulsed magnetic coils into a ~ 30 cm long, 10 cm diameter solid metal can (metal “liner”). The metal liner is then imploded in a z-pinch configuration using a TW-scale pulsed power driver. PdV work from the imploding linear heats the compressed CT plasma to thermonuclear conditions. Though reactor studies indicate that implosion repetition rates only on the order of 1 shot/10 seconds would be required in an MTF reactor (as opposed to ~ 10 Hz for purely laser-driven ICF), continuously delivering such “coke can” size liners and clearing the activated debris at such rates in a reactor presents a daunting engineering challenge. The “plasma liner” concept therefore seeks to replace the metal can with an imploding (gas) plasma liner.
The plasma liner experiment (PLX) at LANL is investigating the feasibility of forming imploding plasma liners with stagnation pressures ~ 100 kPa using a spherical array of high-Z hypervelocity plasma jets. The plasma jets are generated by plasma rail guns manufactured by HyperV Technology Corp., which have demonstrated the acceleration of up to 8 mg of Argon to 50 – 150 km/s, yielding plasma jet parameters n ~ 10^22 m^-3, T ~ 1 eV, Mach numbers, M ~ 20 – 50. The first phase of PLX – now underway - is to study the propagation and expansion of a single jet, and the merging of two jets.
Single and merging jet diagnostics include visible imaging, visible spectroscopy, and a novel 8 chord reconfigurable visible interferometer. The reconfigurable interferometer front end is achieved by fiber-coupling signals to/from the vacuum chamber, and a newly-available long coherence length, diode-pumped solid state laser operating at 561 nm allows pathlength mismatches of many meters to be used without signal degradation, thereby greatly simplifying the system’s optical layout. It has been found that in PLX plasmas interferometer phase shifts are sensitive to neutral and ion density, as well as electron density.
In this talk an overview of MIF and the plasma liner experiment will first be given. The interferometer instrument will then be discussed, and measurements, data analysis, and physics interpretations of single jet and two jet merging studies will be shown.
In the MTF (magnetized target fusion) scheme, a cm-scale compact toroid (CT) with density n ~ 10^22 m^-3, temperature T ~ 100 eV is formed and translated in ~ 10 μs via pulsed magnetic coils into a ~ 30 cm long, 10 cm diameter solid metal can (metal “liner”). The metal liner is then imploded in a z-pinch configuration using a TW-scale pulsed power driver. PdV work from the imploding linear heats the compressed CT plasma to thermonuclear conditions. Though reactor studies indicate that implosion repetition rates only on the order of 1 shot/10 seconds would be required in an MTF reactor (as opposed to ~ 10 Hz for purely laser-driven ICF), continuously delivering such “coke can” size liners and clearing the activated debris at such rates in a reactor presents a daunting engineering challenge. The “plasma liner” concept therefore seeks to replace the metal can with an imploding (gas) plasma liner.
The plasma liner experiment (PLX) at LANL is investigating the feasibility of forming imploding plasma liners with stagnation pressures ~ 100 kPa using a spherical array of high-Z hypervelocity plasma jets. The plasma jets are generated by plasma rail guns manufactured by HyperV Technology Corp., which have demonstrated the acceleration of up to 8 mg of Argon to 50 – 150 km/s, yielding plasma jet parameters n ~ 10^22 m^-3, T ~ 1 eV, Mach numbers, M ~ 20 – 50. The first phase of PLX – now underway - is to study the propagation and expansion of a single jet, and the merging of two jets.
Single and merging jet diagnostics include visible imaging, visible spectroscopy, and a novel 8 chord reconfigurable visible interferometer. The reconfigurable interferometer front end is achieved by fiber-coupling signals to/from the vacuum chamber, and a newly-available long coherence length, diode-pumped solid state laser operating at 561 nm allows pathlength mismatches of many meters to be used without signal degradation, thereby greatly simplifying the system’s optical layout. It has been found that in PLX plasmas interferometer phase shifts are sensitive to neutral and ion density, as well as electron density.
In this talk an overview of MIF and the plasma liner experiment will first be given. The interferometer instrument will then be discussed, and measurements, data analysis, and physics interpretations of single jet and two jet merging studies will be shown.
Practical information
- Informed public
- Free
Organizer
- CRPP
Contact
- Prof. P. Ricci