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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Orbital Period Variation of KIC 10544976: Applegate Mechanism versus Light Travel Time Effect

In recent years, several close post-common-envelope eclipsing binaries have been found to show cyclic eclipse timing variations (ETVs). This effect is usually interpreted either as the gravitational interaction among circumbinary bodies and the host binary—known as the light travel time (LTT) effect—or as the quadrupole moment variations in one magnetic active component—known as the Applegate mechanism. In this study, we present an analysis of the ETV and the magnetic cycle of the close binary KIC 10544976. This system is composed of a white dwarf and a red dwarf in a short orbital period (0.35 days) and was monitored by ground-based telescopes between 2005 and 2017 and by the Kepler satellite between 2009 and 2013. Using the Kepler data, we derived the magnetic cycle of the red dwarf by two ways: the rate and energy of flares and the variability due to spots. Both methods resulted in a cycle of ∼600 days, which is in agreement with magnetic cycles measured for single low-mass stars. The orbital period of KIC 10544976 shows only one long-term variation which can be fitted by an LTT effect with period of ∼16.8 yr. Hence, one possible explanation for the ETVs is the presence of a circumbinary body with a minimal mass of ∼13.4 M {sub Jup}. In the particular scenario of coplanarity between the external body and the inner binary, the third body mass is also ∼13.4 M {sub Jup}. In this case, the circumbinary planet must either have survived the evolution of the host binary or have been formed as a consequence of its evolution.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

SUNSPOT AND STARSPOT LIFETIMES IN A TURBULENT EROSION MODEL

Quantitative models of sunspot and starspot decay predict the timescale of magnetic diffusion and may yield important constraints in stellar dynamo models. Motivated by recent measurements of starspot lifetimes, we investigate the disintegration of a magnetic flux tube by nonlinear diffusion. Previous theoretical studies are extended by considering two physically motivated functional forms for the nonlinear diffusion coefficient D : an inverse power-law dependence D ∝ B {sup −ν} and a step-function dependence of D on the magnetic field magnitude B . Analytical self-similar solutions are presented for the power-law case, including solutions exhibiting “super fast” diffusion. For the step-function case, the heat-balance integral method yields approximate solutions, valid for moderately suppressed diffusion in the spot. The accuracy of the resulting solutions is confirmed numerically, using a method which provides an accurate description of long-time evolution by imposing boundary conditions at infinite distance from the spot. The new models may allow insight into the differences and similarities between sunspots and starspots.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

The Great Solar Active Region NOAA 12192: Helicity Transport, Filament Formation, and Impact on the Polar Field

The solar active region (AR), NOAA 12192, appeared in 2014 October as the largest AR in 24 years. Here we examine the counterintuitive nature of two diffusion-driven processes in the region: the role of helicity buildup in the formation of a major filament, and the relationship between the effects of supergranular diffusion and meridional flow on the AR and on the polar field. Quantitatively, calculations of current helicity and magnetic twist from Helioseismic and Magnetic Imager (HMI) vector magnetograms indicate that, though AR 12192 emerged with negative helicity, positive helicity from subsequent flux emergence, consistent with the hemispheric sign-preference of helicity, increased over time within large-scale, weak-field regions such as those near the polarity inversion line (PIL). Morphologically, Atmospheric Imaging Assembly observations of filament barbs, sigmoidal patterns, and bases of Fe xii stalks initially exhibited signatures of negative helicity, and the long filament that subsequently formed had a strong positive helicity consistent with the helicity buildup along the PIL. We find from full-disk HMI magnetograms that AR 12192's leading positive flux was initially closer to the equator but, owing either to the region’s magnetic surroundings or to its asymmetric flux density distribution, was transported poleward more quickly on average than its trailing negative flux, contrary to the canonical pattern of bipole flux transport. This behavior caused the AR to have a smaller effect on the polar fields than expected and enabled the formation of the very long neutral line where the filament formed.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Empirical Constraints on the Origin of Fast Radio Bursts: Volumetric Rates and Host Galaxy Demographics as a Test of Millisecond Magnetar Connection

The localization of the repeating fast radio burst (FRB) 121102 to a low-metallicity dwarf galaxy at z = 0.193, and its association with a luminous quiescent radio source, suggests the possibility that FRBs originate from magnetars, formed by the unusual supernovae that occur in such galaxies. We investigate this possibility via a comparison of magnetar birth rates, the FRB volumetric rate, and host galaxy demographics. We calculate average volumetric rates of possible millisecond magnetar production channels, such as superluminous supernovae (SLSNe), long and short gamma-ray bursts (GRBs), and general magnetar production via core-collapse supernovae (CCSNe). For each channel, we also explore the expected host galaxy demographics using their known properties. We determine for the first time the number density of FRB emitters (the product of their volumetric birth rate and lifetime), R{sub FRB}τ≈10{sup 4} Gpc{sup −3}, assuming that FRBs are predominantly emitted from repetitive sources similar to FRB 121102 and adopting a beaming factor of 0.1. By comparing rates, we find that production via rare channels (SLSNe, GRBs) implies a typical FRB lifetime of ∼30–300 years, in good agreement with other lines of argument. The total energy emitted over this time is consistent with the available energy stored in the magnetic field. On the other hand, any relation to magnetars produced via normal CCSNe leads to a very short lifetime of ∼0.5 years, in conflict with both theory and observation. We demonstrate that due to the diverse host galaxy distributions of the different progenitor channels, many possible sources of FRB birth can be ruled out with ≲10 host galaxy identifications. Conversely, targeted searches of galaxies that have previously hosted decades-old SLSNe and GRBs may be a fruitful strategy for discovering new FRBs and related quiescent radio sources, and determining the nature of their progenitors.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Plasmoid Instability in Forming Current Sheets

The plasmoid instability has revolutionized our understanding of magnetic reconnection in astrophysical environments. By preventing the formation of highly elongated reconnection layers, it is crucial in enabling the rapid energy conversion rates that are characteristic of many astrophysical phenomena. Most previous studies have focused on Sweet–Parker current sheets, which are unattainable in typical astrophysical systems. Here we derive a general set of scaling laws for the plasmoid instability in resistive and visco-resistive current sheets that evolve over time. Our method relies on a principle of least time that enables us to determine the properties of the reconnecting current sheet (aspect ratio and elapsed time) and the plasmoid instability (growth rate, wavenumber, inner layer width) at the end of the linear phase. After this phase the reconnecting current sheet is disrupted and fast reconnection can occur. The scaling laws of the plasmoid instability are not simple power laws, and they depend on the Lundquist number (S), the magnetic Prandtl number (P m ), the noise of the system (${\psi }_{0}$), the characteristic rate of current sheet evolution ($1/\tau $), and the thinning process. We also demonstrate that previous scalings are inapplicable to the vast majority of astrophysical systems. Furthermore, we explore the implications of the new scaling relations in astrophysical systems such as the solar corona and the interstellar medium. In both of these systems, we show that our scaling laws yield values for the growth rate, wavenumber, and aspect ratio that are much smaller than the Sweet–Parker–based scalings.

Sun: flares↗
DOE OSTI2017

Magnetar Broadband X-Ray Spectra Correlated with Magnetic Fields: Suzaku Archive of SGRs and AXPs Combined with NuSTAR, Swift, and RXTE

The 1–70 keV persistent spectra of 15 magnetars, observed with Suzaku from 2006 to 2013, were studied as a complete sample. Combined with early NuSTAR observations of four hard X-ray emitters, nine objects showed a hard power-law emission dominating at ≳10 keV with the 15–60 keV flux of ∼1–11×10{sup −11} erg s{sup −1} cm{sup −2}. The hard X-ray luminosity L{sub h}, relative to that of a soft-thermal surface radiation L{sub s}, tends to become higher toward younger and strongly magnetized objects. Their hardness ratio, updated from a previous study and defined as ξ=L{sub h}/L{sub s}, is correlated with the measured spin-down rate P-dot as ξ=0.62×( P-dot /10{sup −11}ss{sup −1}){sup 0.72}, corresponding to positive and negative correlations with the dipole field strength B{sub d} (ξ∝B{sub d}{sup 1.41}) and the characteristic age τ{sub c} (ξ∝τ{sub c}{sup −0.68}), respectively. Among our sample, five transients were observed during X-ray outbursts, and the results are compared with their long-term 1–10 keV flux decays monitored with Swift/XRT and RXTE/PCA. Fading curves of three bright outbursts are approximated by an empirical formula used in the seismology, showing a ∼10–40 day plateau phase. Transients show the maximum luminosities of L{sub s} ∼ 10{sup 35} erg s{sup −1}, which are comparable to those of persistently bright ones, and fade back to ≲10{sup 32} erg s{sup −1}. Spectral properties are discussed in the framework of the magnetar hypothesis.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Measuring Filament Orientation: A New Quantitative, Local Approach

The relative orientation between filamentary structures in molecular clouds and the ambient magnetic field provides insight into filament formation and stability. To calculate the relative orientation, a measurement of filament orientation is first required. We propose a new method to calculate the orientation of the one-pixel-wide filament skeleton that is output by filament identification algorithms such as filfinder. We derive the local filament orientation from the direction of the intensity gradient in the skeleton image using the Sobel filter and a few simple post-processing steps. We call this the “Sobel-gradient method.” The resulting filament orientation map can be compared quantitatively on a local scale with the magnetic field orientation map to then find the relative orientation of the filament with respect to the magnetic field at each point along the filament. It can also be used for constructing radial profiles for filament width fitting. The proposed method facilitates automation in analyses of filament skeletons, which is imperative in this era of “big data.”.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

HOT ELECTROMAGNETIC OUTFLOWS. II. JET BREAKOUT

We consider the interaction between radiation, matter, and a magnetic field in a compact, relativistic jet. The entrained matter accelerates outward as the jet breaks out of a star or other confining medium. In some circumstances, such as gamma-ray bursts (GRBs), the magnetization of the jet is greatly reduced by an advected radiation field while the jet is optically thick to scattering. Where magnetic flux surfaces diverge rapidly, a strong outward Lorentz force develops and radiation and matter begin to decouple. The increase in magnetization is coupled to a rapid growth in Lorentz factor. We take two approaches to this problem. The first examines the flow outside the fast magnetosonic critical surface, and calculates the flow speed and the angular distribution of the radiation field over a range of scattering depths. The second considers the flow structure on both sides of the critical surface in the optically thin regime, using a relaxation method. In both approaches, we find how the terminal Lorentz factor and radial profile of the outflow depend on the radiation intensity and optical depth at breakout. The effect of bulk Compton scattering on the radiation spectrum is calculated by a Monte Carlo method, while neglecting the effects of internal dissipation. The peak of the scattered spectrum sits near the seed peak if radiation pressure dominates the acceleration, but is pushed to a higher frequency if the Lorentz force dominates. The unscattered seed radiation can form a distinct, low-frequency component of the spectrum, especially if the magnetic Poynting flux dominates.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Magnetic Navigation for GPS-Denied Airborne Applications

Most current flight systems are dependent on GPS for navigation. Recently, however, navigation in GPS-denied environments has become an area of intensive research. Additional navigation sensor data can be obtained from visual observations (stars or terrain), inertial measurement units, radar, measurements of the local magnetic field, or perhaps even gravity. Absolute and relative positioning via magnetic field measurements have been shown to be viable in many applications including ground navigation, low altitude aircraft flight, and spaceflight. There is greater variability in the magnetic field over shorter distances when flying at low altitude and in ground applications, leading to more accurate positioning. However, ground-based magnetic navigation is often heavily influenced by man-made structures, especially in urban environments. This is not the case for airborne magnetic navigation since the influence of buildings, roads, etc. is negligible for typical aircraft altitudes. For absolute magnetic navigation, the positioning accuracy decreases as altitude increases for a given vehicle velocity, but the observed time variability in the field can be reclaimed by traveling faster through the field. Thus, navigation accuracy becomes a balance of speed and altitude since the higher altitude can be counterbalanced by higher velocity. To understand these effects quantitatively, we explored various techniques to aid a simulated inertial measurement unit with magnetic information. Using a technique known as two-dimensional magnetic map matching, we simulated the performance of airborne magnetic navigation at fixed speed while varying the altitude, flight direction, magnetometer data collection time, reference magnetic map bias error, and type of trajectory (over land or over ocean).

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Massive young stellar object W42-MME: The discovery of an infrared jet using VLT/NACO near-infrared images

We report on the discovery of an infrared jet from a deeply embedded infrared counterpart of the 6.7 GHz methanol maser emission (MME) in W42 (i.e., W42-MME). We show that W42-MME drives a parsec-scale H{sub 2} outflow, with the detection of a bow shock feature at ∼0.52 pc to the north. The inner ∼0.4 pc part of the H{sub 2} outflow has a position angle of ∼18° and the position angle of ∼40° is found farther away on either side of the outflow from W42-MME. W42-MME is detected at wavelengths longer than 2.2 μm and is a massive young stellar object with an estimated stellar mass of 19 ± 4 M{sub ⊙}. We map the inner circumstellar environment of W42-MME using Very Large Telescope (VLT)/NACO adaptive optics K{sub s} and L′ observations at resolutions of ∼0.″ 2 and ∼0.″1, respectively. We discover a collimated jet in the inner 4500 AU using the L′ band, which contains prominent Brα line emission. The jet is located inside an envelope/cavity (extent ∼10,640 AU) that is tapered at both ends and is oriented along the north–south direction. Such observed morphology of the outflow cavity around the massive star is scarcely known and is very crucial for understanding the jet-outflow formation process in massive star formation. Along the flow axis, which is parallel to the previously known magnetic field, two blobs are found in both the NACO images at distances of ∼11800 AU, located symmetrically from W42-MME. The observed W42-MME jet-outflow configuration can be used to constrain the jet launching and jet collimation models in massive star formation.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

The JCMT BISTRO Survey: The Magnetic Field Strength in the Orion A Filament

We determine the magnetic field strength in the OMC 1 region of the Orion A filament via a new implementation of the Chandrasekhar–Fermi method using observations performed as part of the James Clerk Maxwell Telescope (JCMT) B-Fields In Star-forming Region Observations (BISTRO) survey with the POL-2 instrument. We combine BISTRO data with archival SCUBA-2 and HARP observations to find a plane-of-sky magnetic field strength in OMC 1 of B{sub pos}=6.6±4.7 mG, where δB{sub pos}=4.7 mG represents a predominantly systematic uncertainty. We develop a new method for measuring angular dispersion, analogous to unsharp masking. We find a magnetic energy density of ∼1.7×10{sup −7} J m{sup −3} in OMC 1, comparable both to the gravitational potential energy density of OMC 1 (∼10{sup −7} J m{sup −3}) and to the energy density in the Orion BN/KL outflow (∼10{sup −7} J m{sup −3}). We find that neither the Alfvén velocity in OMC 1 nor the velocity of the super-Alfvénic outflow ejecta is sufficiently large for the BN/KL outflow to have caused large-scale distortion of the local magnetic field in the ∼500 yr lifetime of the outflow. Hence, we propose that the hourglass field morphology in OMC 1 is caused by the distortion of a primordial cylindrically symmetric magnetic field by the gravitational fragmentation of the filament and/or the gravitational interaction of the BN/KL and S clumps. We find that OMC 1 is currently in or near magnetically supported equilibrium, and that the current large-scale morphology of the BN/KL outflow is regulated by the geometry of the magnetic field in OMC 1, and not vice versa.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

NEAR-INFRARED CIRCULAR POLARIZATION SURVEY IN STAR-FORMING REGIONS: CORRELATIONS AND TRENDS

We have conducted a systematic near-infrared circular polarization (CP) survey in star-forming regions, covering high-mass, intermediate-mass, and low-mass young stellar objects. All the observations were made using the SIRPOL imaging polarimeter on the Infrared Survey Facility 1.4 m telescope at the South African Astronomical Observatory. We present the polarization properties of 10 sub-regions in 6 star-forming regions. The polarization patterns, extents, and maximum degrees of linear and circular polarizations are used to determine the prevalence and origin of CP in the star-forming regions. Our results show that the CP pattern is quadrupolar in general, the CP regions are extensive, up to 0.65 pc, the CP degrees are high, up to 20%, and the CP degrees decrease systematically from high- to low-mass young stellar objects. The results are consistent with dichroic extinction mechanisms generating the high degrees of CP in star-forming regions.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

MAGNETIC EFFECTS AND OVERSIZED M DWARFS IN THE YOUNG OPEN CLUSTER NGC 2516

By combining rotation periods with spectroscopic determinations of projected rotation velocity, Jackson et al. have found that the mean radii for low-mass M-dwarfs in the young, open cluster NGC 2516 are larger than model predictions at a given absolute I magnitude or I - K color and also larger than measured radii of magnetically inactive M-dwarfs. The relative radius difference is correlated with magnitude, increasing from a few percent at M{sub I} = 7 to greater than 50% for the lowest luminosity stars in their sample at M{sub I} {approx} 9.5. Jackson et al. have suggested that a two-temperature star spot model is capable of explaining the observations, but their model requires spot coverage fractions of at least 50% in rapidly rotating M-dwarfs. Here we examine these results in terms of stellar models that include the inhibiting effects of magnetic fields on convective energy transport, with and without the effects of star spots. We find that a pure spot model is inconsistent with the color-magnitude diagram. The observations of radii versus color and radii versus absolute magnitude in NGC 2516 are consistent with models which include only magnetic inhibition or a combination of magnetic inhibition and spots. At a given mass we find a large dispersion in the strength of the vertical component of the magnetic field in the stellar photosphere but the general trend is that the vertical field increases with decreasing mass from a few hundred Gauss at 0.65 M{sub Sun} to 600-900 G, depending on spot coverage, in the lowest mass stars in the sample at 0.25 M{sub Sun }.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

Kiloparsec-scale simulations of star formation in disk galaxies. III. Structure and dynamics of filaments and clumps in giant molecular clouds

We present hydrodynamic simulations of self-gravitating dense gas in a galactic disk, exploring scales ranging from 1 kpc down to ∼0.1 pc. Our primary goal is to understand how dense filaments form in giant molecular clouds (GMCs). These structures, often observed as infrared dark clouds (IRDCs) in the Galactic plane, are thought to be the precursors to massive stars and star clusters, so their formation may be the rate-limiting step controlling global star formation rates in galactic systems as described by the Kennicutt–Schmidt relation. Our study follows on from Van Loo et al., which carried out simulations to 0.5 pc resolution and examined global aspects of the formation of dense gas clumps and the resulting star formation rate. Here, using our higher resolution, we examine the detailed structural, kinematic, and dynamical properties of dense filaments and clumps, including mass surface density (Σ) probability distribution functions, filament mass per unit length and its dispersion, lateral Σ profiles, filament fragmentation, filament velocity gradients and infall, and degree of filament and clump virialization. Where possible, these properties are compared to observations of IRDCs. By many metrics, especially too large mass fractions of high Σ>1 g cm{sup −2} material, too high mass per unit length dispersion due to dense clump formation, too high velocity gradients, and too high velocity dispersion for a given mass per unit length, the simulated filaments differ from observed IRDCs. We thus conclude that IRDCs do not form from global fast collapse of GMCs. Rather, we expect that IRDC formation and collapse are slowed significantly by the influence of dynamically important magnetic fields, which may thus play a crucial role in regulating galactic star formation rates.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

High-energy neutrino emission from magnetized jets of rapidly rotating protomagnetars

ABSTRACT Relativistic jets originating from protomagnetar central engines can lead to long duration gamma-ray bursts (GRBs) and are considered potential sources of ultra-high-energy cosmic rays and secondary neutrinos. We explore the propagation of such jets through a broad range of progenitors, from stars which have shed their envelopes to supergiants which have not. We use a semi-analytical spin-down model for the strongly magnetized and rapidly rotating protoneutron star (PNS) to investigate the role of central engine properties such as the surface dipole field strength, initial rotation period, and jet opening angle on the interactions and dynamical evolution of the jet-cocoon system. With this model, we determine the properties of the relativistic jet, the mildly relativistic cocoon, and the collimation shock in terms of system parameters such as the time-dependent jet luminosity, injection angle, and density profile of the stellar medium. We also analyse the criteria for a successful jet breakout, the maximum energy that can be deposited into the cocoon by the relativistic jet, and structural stability of the magnetized outflow relative to local instabilities. Lastly, we compute the high-energy neutrino emission as these magnetized outflows burrow through their progenitors. Precursor neutrinos from successful GRB jets are unlikely to be detected by IceCube, which is consistent with the results of previous works. On the other hand, we find that high-energy neutrinos may be produced for extended progenitors like blue and red supergiants, and we estimate the detectability of neutrinos with next generation detectors such as IceCube-Gen2.

Astronomy & Astrophysics↗
DOE OSTI2013

The dynamical state of the Serpens South filamentary infrared dark cloud

We present the results of N{sub 2}H{sup +} (J = 1-0) observations toward Serpens South, the nearest cluster-forming, infrared dark cloud. The physical quantities are derived by fitting the hyperfine structure of N{sub 2}H{sup +}. The Herschel and 1.1 mm continuum maps show that a parsec-scale filament fragments into three clumps with radii of 0.1-0.2 pc and masses of 40-230 M {sub ☉}. We find that the clumps contain smaller-scale (∼0.04 pc) structures, i.e., dense cores. We identify 70 cores by applying CLUMPFIND to the N{sub 2}H{sup +} data cube. In the central cluster-forming clump, the excitation temperature and line-width tend to be large, presumably due to protostellar outflow feedback and stellar radiation. However, for all the clumps, the virial ratios are evaluated to be 0.1-0.3, indicating that the internal motions play only a minor role in the clump support. The clumps exhibit no free fall but exhibit low-velocity infall, and thus the clumps should be supported by additional forces. The most promising force is the globally ordered magnetic field observed toward this region. We propose that the Serpens South filament was close to magnetically critical and ambipolar diffusion triggered the cluster formation. We find that the northern clump, which shows no active star formation, has a mass and radius comparable to the central cluster-forming clump and is therefore a likely candidate of a pre-protocluster clump. The initial condition for cluster formation is likely to be a magnetically supported clump of cold, quiescent gas. This appears to contradict the accretion-driven turbulence scenario, for which the turbulence in the clumps is maintained by the accretion flow.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

Gravitational waves from rotating neutron stars: Current limits and prospects

Rotating neutron stars that emit continuous gravitational waves are among promising targets of the LIGO and Virgo detectors: sufficiently large non-axisymmetrie deformation w.r.t. the axis of rotation of a star generates a time-varying mass-quadrupole moment and henceforth gravitational wave emission. The departure from an axisymmetrie shape may be caused by the internal magnetic field and/or elastic stresses in the crust/core. If detected, it will provide novel insight into the presently obscured details of the interior neutron-star structure. This talk presents basic types of searches for such signals: from targeted searches from known pulsars to all-sky wide parameter searches for unknown objects. Selected methods used in the data analysis and to calculate the upper limits on the gravitational waves in the initial phase of LIGO and Virgo projects are briefly described. Observational results of LIGO and Virgo collaborations include “beating” the spin-down limit for the Crab and Vela pulsars [7, 11], search for a coherent signal from the direction of the Cas A supernova remnant [5], as well as the Galactic center [1], SN1987A and the Sco-X1 binary with the cross-correlation method [6], and the all-sky searches for signals of unknown position and frequency [2, 4, 8].

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

A Star on Earth

At the Energy Department's Princeton Plasma Physics Lab, scientists are trying to accomplish what was once considered the realm of science fiction: create a star on Earth. The National Spherical Torus Experiment (NSTX) is a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas -- hot ionized gases in which, under the right conditions, nuclear fusion will occur. Fusion is the energy source of the sun and all of the stars. Not just limited to theoretical work, the NSTX is enabling cutting-edge research to develop fusion as a future energy source.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗