Dynamics of a Z-pinch x-ray source for heating inertial-confinement-fusion relevant hohlraums to 120–160 eV

Sanford, T.W.L.; Olson, R. E.; Mock, R. C.; Chandler, G. A.; Leeper, R. J.; Nash, T. J.; Ruggles, L. E.; Simpson, W. W.; Struve, K. W.; Bowers, R.L.; Matuska, W.

doi:10.1063/1.1316087

Cited by 46 publications

(28 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dynamic-hohlraums (DHs) [1][2][3][4] driven by a wire-array z-pinch are being developed and used as intense blackbody x-ray sources for inertialconfinement-fusion (ICF) [5][6][7][8][9] and hightemperature radiation-flow experiments [10][11] (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Overview of the dynamic-hohlraum x-ray source at Sandia National Laboratories.

Report¹

2007

View full text Add to dashboard Cite

Progress in understanding the physics of Dynamic-Hohlraums is reviewed for a system capable of generating 10 TW of axial radiation for high temperature (>200 eV) radiation-flow experiments and ICF capsule implosions. 2D magneto-hydrodynamic simulation comparisons with data show the need to include wire initiation physics and subsequent discrete wire dynamics in the simulations if a predictive capability is to be achieved.

show abstract

Section: Introductionmentioning

confidence: 99%

Overview of the dynamic-hohlraum x-ray source at Sandia National Laboratories.

Report¹

2007

View full text Add to dashboard Cite

show abstract

“…They also neglect Rayleigh-Taylor instabilities, an approximation justified by Ref. [5,6,8]. The radiation field at the capsule location was calculated by integrating the radiation transport equation within the ZPDH.…”

mentioning

confidence: 99%

“…The experiments used the Z facility [2,3] to drive a ZPDH configuration [3,5,8] composed of concentric annular tungsten wire arrays with a 240-wire 40-mm-diameter outer array and a 120-wire 20-mm-diameter inner array. The wire diameter was 7.5 µm.…”

mentioning

confidence: 99%

“…Polar line of sight measurements were performed through a 4-mm-diameter aperture that was covered with a 4 µm Ti + 2 µm CH foil to reduce symmetry perturbations. The time-dependent radiation temperature, shock, and capsule radius were diagnosed using x-ray imaging and power measurements [5,8,9]. The~18 Mbar shock had a~35 cm/µsec velocity and the peak radiation drive temperature was~220 eV, prior to the arrival of the shock on axis.…”

mentioning

confidence: 99%

“…The capsule core xray emission peaked 2-3 ns before shock arrival on axis and 4-5 ns prior to z-pinch stagnation. The times given below are with respect to z-pinch stagnation, as defined in [8]. The diagnostic suite [10] included capsule implosion time measurements using filtered photoconducting diodes and both activation and time-of-flight neutron detectors.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Hot Dense Capsule-Implosion Cores Produced byZ-Pinch Dynamic Hohlraum Radiation

et al. 2004

Self Cite

View full text Add to dashboard Cite

Hot dense capsule implosions driven by z-pinch x-rays have been measured for the first time. A ~220 eV dynamic hohlraum imploded 1.7-2.1 mm diameter gas-filled CH capsules which absorbed up to ~20 kJ of x-rays. Argon tracer atom spectra were used to measure the T e ~1 keV electron temperature and the n e ~1-4 x 10 23 cm -3 electron density. Spectra from multiple directions provide core symmetry estimates. Computer simulations agree well with the peak compression values of T e , n e , and symmetry, indicating reasonable understanding of the hohlraum and implosion physics.Implosion of spherical capsules by x-rays contained in an enclosure known as a hohlraum is the baseline approach for achieving inertial confinement fusion (ICF) [1]. These implosions provide a platform for high energy density physics investigations and may enable studies of matter at conditions similar to stellar interiors. One method for generating the required high energy density x-rays is the z-pinch dynamic hohlraum (ZPDH) [2][3][4]. Accelerating an annular high-atomic-number zpinch plasma onto a low-atomic-number low-density cylindrical foam creates this type of hohlraum. The z-pinch plasma impact onto the foam launches a radiating shock that propagates toward the cylinder axis and heats the hohlraum. The z-pinch plasma traps the radiation, improving the symmetry for driving capsule implosions at the center of the hohlraum. In this Letter we describe the first x-ray measurements of hot dense implosion cores produced using z-pinch radiation drive.ICF requires highly-symmetric capsule implosions. Absorption of 150 kJ of x-ray energy in a carefully-shaped pulse with ~1-3 % spatial symmetry is estimated to be sufficient for ignition [1].The appeal of the ZPDH approach is efficient generation and delivery of x-rays to the capsule. Indeed, the capsules in the experiments reported here absorbed up to 20 kJ of x-rays, about 1/8 of the estimated ignition requirement. However, it remains to be seen whether adequate symmetry and temporal pulse shaping control can be obtained. The experiments reported here represent an important step toward ZPDH symmetry control.Recent work [5][6] demonstrated reasonable ZPDH performance understanding. The effect of random z-pinch non-uniformities on the shock radiation source was found very small. The systematic asymmetries must now be addressed. The cylindrical ZPDH tends to drive the spherical capsule with equator-hot radiation that, if uncorrected, will produce an implosion elongated along the cylinder axis. Symmetry corrections, including radiation shields, non-cylindrical foams, and local foam dopants, require diagnostics capable of measuring the alteration's effect. Published laser driven implosions [7] showed that x-ray core imaging measurements of the equatorial plane radius (a) compared to the polar radius (b) reflected the x-ray drive asymmetry. Applying this method to the ZPDH is complicated by the difficulty of viewing the implosion through the luminous highopacity z-pinch plasma (Fig. 1). We consequently em...

show abstract

Heterogeneous Plasma‐Producing Structures at Current Implosion of a Wire Array

Grabovsky

Mitrofanov

Nedoseev

et al. 2005

Contrib. Plasma Phys.

View full text Add to dashboard Cite

Characteristic properties of the plasma production process have been considered for the case of megampere currents flowing through hollow cylindrical wire arrays of the Angara-5-1 facility. In 3-4 nanoseconds after voltage applying to the wire surfaces there appear a plasma layer. The system becomes heterogeneous, i.e. consisting of a kernel of metal wires and a plasma layer. In several nanoseconds the current flow goes from metal to plasma, which results in reducing the electric field strength along the wire.The Joule heat energy delivered to the metal before the moment of complete current trapping by plasma is insufficient for the whole mass transition to a hot plasma state. The X-ray radiography techniques made it possible to detect and study dense clusters of substance of ∼1g/cm 3 at a developed discharge stage. The radial expansion velocity of ∼10 4 cm/s measured at the 70-th nanosecond after the current start allows treating the dense core at a late stage in the form of a submicron heterogeneous structure from its liquid and slightly ionized gas phase.

show abstract

Dynamics of a Z-pinch x-ray source for heating inertial-confinement-fusion relevant hohlraums to 120–160 eV

Cited by 46 publications

References 48 publications

Overview of the dynamic-hohlraum x-ray source at Sandia National Laboratories.

Overview of the dynamic-hohlraum x-ray source at Sandia National Laboratories.

Hot Dense Capsule-Implosion Cores Produced byZ-Pinch Dynamic Hohlraum Radiation

Heterogeneous Plasma‐Producing Structures at Current Implosion of a Wire Array

Contact Info

Product

Resources

About