Experimental characterization of railgun-driven supersonic plasma jets motivated by high energy density physics applications

Hsu, S. C.; Merritt, E. C.; Moser, Auna; Awe, T. J.; Brockington, Samuel; Davis, Joel; Adams, C. S.; Case, Andrew; Cassibry, Jason; Dunn, J. P.; Gilmore, M.; Lynn, A. G.; Messer, Sarah; Witherspoon, F. D.

doi:10.1063/1.4773320

Cited by 51 publications

(45 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…LANL also leads a team that is exploring a standoff concept of using a spherically convergent array of gun-driven plasma jets to Fig. 1 Many of the MIF concepts presently being explored in the USA achieve assembly and implosion of a plasma liner (PLX) without the need to destroy material liners or transmission lines on each shot [17][18][19][20]. A private company, general fusion (GF) in Canada, with many Americans working for it, is developing a merging compact toroid plasma source and envisions repetitively fired acoustic drivers that would drive a liquid liner compression of a magnetized target [21][22][23].…”

Section: Statusmentioning

confidence: 99%

“…To test the possibility of a standoff driver [34,35] (one without physical leads to the liner thus avoiding repetitive hardware destruction), a plasma liner formed from multiple plasma jets [17,18] is being pursued again at LANL, i.e., plasma-jet-driven MIF or PJMIF, funded by an ARPA-E for the next 3 years under its accelrating low-cost plasma heating and assembly (ALPHA) program. A 2.7-meter diameter spherical vacuum chamber is the centerpiece of the plasma liner experiment (PLX) at LANL, which has also conducted basic plasma shock experiments [19,20,36,37] using two plasma railguns that were developed by HyperV Technologies Corporation.…”

Section: Recent Progressmentioning

confidence: 99%

See 1 more Smart Citation

Magneto-Inertial Fusion

et al. 2015

Self Cite

View full text Add to dashboard Cite

In this community white paper, we describe an approach to achieving fusion which employs a hybrid of elements from the traditional magnetic and inertial fusion concepts, called magneto-inertial fusion (MIF). The status of MIF research in North America at multiple institutions is summarized including recent progress, research opportunities, and future plans.Keywords Magneto-inertial fusion Á Magnetized target fusion Á Liner Á Plasma jets Á Fusion energy Á MagLIF DescriptionMagneto-inertial fusion (MIF) (aka magnetized target fusion) [1][2][3] is an approach to fusion that combines the compressional heating of inertial confinement fusion (ICF) with the magnetically reduced thermal transport and magnetically enhanced alpha heating of magnetic confinement fusion (MCF). From an MCF perspective, the higher density, shorter confinement times, and compressional heating as the dominant heating mechanism reduce the impact of instabilities. From an ICF perspective, the primary benefits are potentially orders of magnitude reduction in the difficult to achieve qr parameter (areal density), and potentially significant reduction in velocity requirements and hydrodynamic instabilities for compression drivers. In fact, ignition becomes theoretically possible from qr B 0.01 g/cm 2 up to conventional ICF values of qr * 1.0 g/cm 2 , and as in MCF, Br rather than qr becomes the key figure-of-merit for ignition because of the enhanced alpha deposition [4]. Within the lower-qr parameter space, MIF exploits lower required implosion velocities (2-100 km/s, compared to the ICF minimum of 350-400 km/s) allowing the use of much more efficient (g C 0.3) pulsed power drivers, while at the highest (i.e., ICF) end of the qr range, both higher gain G at a given implosion velocity as well as lower implosion velocity and reduced hydrodynamic instabilities are theoretically possible. To avoid confusion, it must be emphasized that the wellknown conventional ICF burn fraction formula does not apply for the lower-qr ''liner-driven'' MIF schemes, since it is the much larger mass and qr of the liner (and not that of the burning fuel) that determines the ''dwell time'' and fuel burnup fraction. In all cases, MIF approaches seek to satisfy/ exceed the inertial fusion energy (IFE) figure-of-merit gG * 7-10 required in an economical plant with reasonable recirculating power fraction. A great advantage of MIF is indeed its extremely wide parameter space which allows it greater versatility in overcoming difficulties in implementation or technology, as evidenced by the four diverse approaches and associated implosion velocities shown in Fig. 1.MIF approaches occupy an attractive region in thermonuclear q-T parameter space, as shown in a paper by

show abstract

Section: Statusmentioning

confidence: 99%

Section: Recent Progressmentioning

confidence: 99%

Magneto-Inertial Fusion

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Prior experiments studying the stagnation layer between colliding laser-produced or wire-array z-pinch [33] plasmas were on smaller spatial scales (mm or smaller) that could not be fully resolved by measurements. New results in the present work are the experimental identification and characterization of a few-cm thick stagnation layer between colliding plasmas, and the demonstration that our observations are consistent with hydrodynamic oblique shock theory [34].Experiments reported here are conducted on the Plasma Liner Experiment (PLX) [35], in which two supersonic argon plasma jets are formed and launched by plasma railguns [36]. Plasma jet parameters at the exit of the railgun nozzle (peak n e ≈ 2 × 10 16 cm −3 , peak T e ≈ 1.4 eV, V jet ≈ 30 km/s, Mach number M ≡ V jet /C s,jet ≈ 14, diameter = 5 cm, and length ≈ 20 cm) and their evolution during subsequent jet propagation have been characterized in detail [35].…”

mentioning

confidence: 99%

“…Plasma jet parameters at the exit of the railgun nozzle (peak n e ≈ 2 × 10 16 cm −3 , peak T e ≈ 1.4 eV, V jet ≈ 30 km/s, Mach number M ≡ V jet /C s,jet ≈ 14, diameter = 5 cm, and length ≈ 20 cm) and their evolution during subsequent jet propagation have been characterized in detail [35]. The jet magnetic field inside the railgun is ∼3 T, but the classical magnetic diffusion time is a few µs [35], and thus • apart, two merging plasma jets, R-Z coordinates used in the paper, approximate interferometer/spectrometer linesof-sight (Z ≈ 84 cm), and CCD camera field-of-view.we ignore the effects of a magnetic field by the time of jet merging (> 20 µs). Experimental data are from an eight-chord laser (561 nm) interferometer [37,38], a visible-to-near-infrared 0.275 m survey spectrometer (600 lines/mm grating and 0.45 µs gating on the 1024-pixel MCP array detector), and an intensified chargecoupled device (CCD) visible-imaging camera (DiCam Pro, 1280 × 1024 pixels, 12-bit dynamic range).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Experimental Characterization of the Stagnation Layer between Two Obliquely Merging Supersonic Plasma Jets

Merritt

Hsu

et al. 2013

Phys. Rev. Lett.

Self Cite

View full text Add to dashboard Cite

We present spatially resolved measurements characterizing the stagnation layer between two obliquely merging supersonic plasma jets. Intra-jet collisionality is very high (λii ≪ 1 mm), but the inter-jet ion-ion mean free paths are on the same order as the stagnation layer thickness (a few cm). Fast-framing camera images show a double-peaked emission profile transverse to the stagnation layer, with the central emission dip consistent with a density dip observed in the interferometer data. We demonstrate that our observations are consistent with collisional oblique shocks.Colliding plasmas have been studied in a variety of contexts, e.g., counterstreaming laser-produced plasmas supporting hohlraum design for indirect-drive inertial confinement fusion [1][2][3], forming and studying astrophysically relevant shocks [4][5][6][7][8], and for applications such as pulsed laser deposition [9] and laser-induced breakdown spectroscopy [10]. Physics issues arising in these studies include plasma interpenetration [11][12][13][14][15][16], shock formation [17], and the formation and dynamics of a stagnation layer [18][19][20]. In this work, we present experimental results on two obliquely merging supersonic plasma jets, which are in a different and more collisional parameter regime than many of the colliding plasma examples mentioned above. Ours and other recent jet-merging experiments [21,22] were conducted to explore the feasibility of forming imploding spherical plasma liners via an array of merging plasma jets [23][24][25][26][27], which could have applications in forming cm-, µs-, and Mbar-scale plasmas for fundamental high-energy-density-physics studies [28] and as a standoff driver for magnetoinertial fusion [23,[29][30][31][32]. Prior experiments studying the stagnation layer between colliding laser-produced or wire-array z-pinch [33] plasmas were on smaller spatial scales (mm or smaller) that could not be fully resolved by measurements. New results in the present work are the experimental identification and characterization of a few-cm thick stagnation layer between colliding plasmas, and the demonstration that our observations are consistent with hydrodynamic oblique shock theory [34].Experiments reported here are conducted on the Plasma Liner Experiment (PLX) [35], in which two supersonic argon plasma jets are formed and launched by plasma railguns [36]. Plasma jet parameters at the exit of the railgun nozzle (peak n e ≈ 2 × 10 16 cm −3 , peak T e ≈ 1.4 eV, V jet ≈ 30 km/s, Mach number M ≡ V jet /C s,jet ≈ 14, diameter = 5 cm, and length ≈ 20 cm) and their evolution during subsequent jet propagation have been characterized in detail [35]. The jet magnetic field inside the railgun is ∼3 T, but the classical magnetic diffusion time is a few µs [35], and thus • apart, two merging plasma jets, R-Z coordinates used in the paper, approximate interferometer/spectrometer linesof-sight (Z ≈ 84 cm), and CCD camera field-of-view.we ignore the effects of a magnetic field by the time of jet merging (> 20 µs). Experimental data ...

show abstract

Physics Criteria for a Subscale Plasma Liner Experiment

Hsu

Thio

2018

J Fusion Energ

View full text Add to dashboard Cite

Spherically imploding plasma liners, formed by merging hypersonic plasma jets, are a proposed standoff driver to compress magnetized target plasmas to fusion conditions [S. C. Hsu et al., IEEE Trans. Plasma Sci. 40, 1287 (2012)]. In this paper, the parameter space and physics criteria are identified for a subscale, plasmaliner-formation experiment to provide data, e.g., on liner ram-pressure scaling and uniformity, that are relevant for addressing scientific issues of full-scale plasma liners required to achieve fusion conditions. Based on these criteria, we quantitatively estimate the minimum liner kinetic energy and mass needed, which informed the design of a subscale plasma liner experiment now under development.

show abstract

Experimental characterization of railgun-driven supersonic plasma jets motivated by high energy density physics applications

Cited by 51 publications

References 37 publications

Magneto-Inertial Fusion

Magneto-Inertial Fusion

Experimental Characterization of the Stagnation Layer between Two Obliquely Merging Supersonic Plasma Jets

Physics Criteria for a Subscale Plasma Liner Experiment

Contact Info

Product

Resources

About