Mass ablation and magnetic flux losses through a magnetized plasma-liner wall interface

2017 ◽  
Vol 24 (7) ◽  
pp. 072710 ◽  
Author(s):  
F. García-Rubio ◽  
J. Sanz
Keyword(s):  
Magnetic Flux ◽  
Magnetized Plasma ◽  
Plasma Liner

scholarly journals Formation of transient high-β plasmas in a magnetized, weakly collisional regime

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
T. Byvank ◽  
D. A. Endrizzi ◽  
C. B. Forest ◽  
S. J. Langendorf ◽  
K. J. McCollam ◽  
...  
Keyword(s):  
Experimental Data ◽  
Magnetic Flux ◽  
Plasma Physics ◽  
System Size ◽  
Magnetic Pressure ◽  
Magnetized Plasma ◽  
Inertial Fusion ◽  
Thermal Pressure ◽  
Astrophysical Objects ◽  
Collisional Regime

We present experimental data providing evidence for the formation of transient ( ${\sim }20\ \mathrm {\mu }\textrm {s}$ ) plasmas that are simultaneously weakly magnetized (i.e. Hall magnetization parameter $\omega \tau > 1$ ) and dominated by thermal pressure (i.e. ratio of thermal-to-magnetic pressure $\beta > 1$ ). Particle collisional mean free paths are an appreciable fraction of the overall system size. These plasmas are formed via the head-on merging of two plasmas launched by magnetized coaxial guns. The ratio $\lambda _{\textrm {gun}}=\mu _0 I_{\textrm {gun}}/\psi _{\textrm {gun}}$ of gun current $I_{\textrm {gun}}$ to applied magnetic flux $\psi _{\textrm {gun}}$ is an experimental knob for exploring the parameter space of $\beta$ and $\omega \tau$ . These experiments were conducted on the Big Red Ball at the Wisconsin Plasma Physics Laboratory. The transient formation of such plasmas can potentially open up new regimes for the laboratory study of weakly collisional, magnetized, high- $\beta$ plasma physics; processes relevant to astrophysical objects and phenomena; and novel magnetized plasma targets for magneto-inertial fusion.

scholarly journals X-ray jets and magnetic flux emergence in the Sun

2008 ◽  
Vol 4 (S259) ◽  
pp. 201-210
Author(s):  
Fernando Moreno-Insertis
Keyword(s):  
Magnetic Flux ◽  
Solar Atmosphere ◽  
Numerical Experiments ◽  
High Speed ◽  
Computational Effort ◽  
Plasma Jets ◽  
Solar Interior ◽  
Magnetized Plasma ◽  
Flux Emergence ◽  
X Ray

AbstractMagnetized plasma is emerging continually from the solar interior into the atmosphere. Magnetic flux emergence events and their consequences in the solar atmosphere are being observed with high space, time and spectral resolution by a large number of space missions in operation at present (e.g. SOHO, Hinode, Stereo, Rhessi). The collision of an emerging and a preexisting magnetic flux system in the solar atmosphere leads to the formation of current sheets and to field line reconnection. Reconnection under solar coronal conditions is an energetic event; for the field strengths, densities and speeds involved in the collision of emerging flux systems, the reconnection outflows lead to launching of high-speed (hundreds of km/s), high-temperature (107 K) plasma jets. Such jets are being observed with the X-Ray and EUV detectors of ongoing satellite missions. On the other hand, the spectacular increase in computational power in recent years permits to carry out three-dimensional numerical experiments of the time evolution of flux emerging systems and the launching of jets with a remarkable degree of detail.In this review, observation and modeling of the solar X-Ray jets are discussed. A two-decade long computational effort to model the magnetic flux emergence events by different teams has led to numerical experiments which explain, even quantitatively, many of the observed features of the X-ray jets. The review points out that, although alternative mechanisms must be considered, flux emergence is a prime candidate to explain the launching of the solar jets.

scholarly journals Laboratory simulation of solar magnetic flux rope eruptions

2010 ◽  
Vol 6 (S273) ◽  
pp. 483-486
Author(s):  
S. K. P. Tripathi ◽  
W. Gekelman
Keyword(s):  
Magnetic Flux ◽  
Flux Rope ◽  
Magnetized Plasma ◽  
Three Dimensions ◽  
Laboratory Simulation ◽  
Laboratory Plasma ◽  
Magnetic Flux Ropes ◽  
Solar Prominences ◽  
Plasma Experiment ◽  
Spatio Temporal

AbstractA laboratory plasma experiment has been constructed to simulate the eruption of arched magnetic flux ropes (AMFRs e.g., coronal loops, solar prominences) in an ambient magnetized plasma. The laboratory AMFR is produced using an annular hot LaB6 cathode and an annular anode in a vacuum chamber which has additional electrodes to produce the ambient magnetized plasma. Two laser beams strike movable carbon targets placed behind the annular electrodes to generate controlled plasma flows from the AMFR footpoints that drives the AMFR eruption. The experiment operates with a 0.5 Hz repetition rate and is highly reproducible. Thus, time evolution of the AMFR is recorded in three-dimensions with high spatio-temporal resolutions using movable diagnostic probes. Experimental results demonstrate outward expansion of the AMFR, release of its plasma to the background, and excitation of fast magnetosonic waves during the eruption.

Performance analysis of magnetic flux compression by plasma liner

2010 ◽  
Vol 2 (3) ◽  
pp. 375-387 ◽  
Author(s):  
V. A. Gasilov ◽  
S. V. D’yachenko ◽  
A. S. Chuvatin ◽  
O. G. Ol’khovskaya ◽  
A. S. Boldarev ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Magnetic Flux ◽  
Plasma Liner ◽  
Flux Compression ◽  
Magnetic Flux Compression

scholarly journals Structure of a Magnetic Flux Annihilation Layer Formed by the Collision of Supersonic, Magnetized Plasma Flows

2016 ◽  
Vol 116 (22) ◽  
Author(s):  
L. G. Suttle ◽  
J. D. Hare ◽  
S. V. Lebedev ◽  
G. F. Swadling ◽  
G. C. Burdiak ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Magnetized Plasma ◽  
Plasma Flows

Hamiltonian vortices and reconnection in a magnetized plasma

1998 ◽  
Vol 59 (4) ◽  
pp. 727-736 ◽  
Author(s):  
B. N. KUVSHINOV ◽  
V. P. LAKHIN ◽  
F. PEGORARO ◽  
T. J. SCHEP
Keyword(s):  
Magnetic Flux ◽  
Euler Equation ◽  
Fluid Model ◽  
Magnetized Plasma ◽  
Two Dimensional ◽  
Magnetic Islands ◽  
Electron Momentum ◽  
Lagrangian Form ◽  
Two Fluid Model ◽  
Two Fluid

Hamiltonian vortices and reconnection in magnetized plasmas are investigated analytically and numerically using a two-fluid model. The equations are written in the Lagrangian form of three fields that are advected with different velocities. This system can be considered as a generalization and extension of the two-dimensional Euler equation for an ordinary fluid. It is pointed out that these equations allow solutions in the form of singular current-vortex filaments, drift-Alfvén vortices and magnetic islands, and admit collisionless magnetic reconnection where magnetic flux is converted into electron momentum and ion vorticity.

scholarly journals Black Hole Flares: Ejection of Accreted Magnetic Flux through 3D Plasmoid-mediated Reconnection

2022 ◽  
Vol 924 (2) ◽  
pp. L32
Author(s):  
B. Ripperda ◽  
M. Liska ◽  
K. Chatterjee ◽  
G. Musoke ◽  
A. A. Philippov ◽  
...  
Keyword(s):  
Black Holes ◽  
Magnetic Flux ◽  
Current Sheet ◽  
High Energy ◽  
Magnetized Plasma ◽  
Low Density ◽  
Very High Energy ◽  
General Relativistic ◽  
Sgr A ◽  
Relativistic Magnetohydrodynamics

Abstract Magnetic reconnection can power bright, rapid flares originating from the inner magnetosphere of accreting black holes. We conduct extremely high-resolution (5376 × 2304 × 2304 cells) general-relativistic magnetohydrodynamics simulations, capturing plasmoid-mediated reconnection in a 3D magnetically arrested disk for the first time. We show that an equatorial, plasmoid-unstable current sheet forms in a transient, nonaxisymmetric, low-density magnetosphere within the inner few Schwarzschild radii. Magnetic flux bundles escape from the event horizon through reconnection at the universal plasmoid-mediated rate in this current sheet. The reconnection feeds on the highly magnetized plasma in the jets and heats the plasma that ends up trapped in flux bundles to temperatures proportional to the jet’s magnetization. The escaped flux bundles can complete a full orbit as low-density hot spots, consistent with Sgr A* observations by the GRAVITY interferometer. Reconnection near the horizon produces sufficiently energetic plasma to explain flares from accreting black holes, such as the TeV emission observed from M87. The drop in the mass accretion rate during the flare and the resulting low-density magnetosphere make it easier for very-high-energy photons produced by reconnection-accelerated particles to escape. The extreme-resolution results in a converged plasmoid-mediated reconnection rate that directly determines the timescales and properties of the flare.

Evolutionary Characteristics of Large-Scale Magnetic and Velocity Fields

1993 ◽  
Vol 141 ◽  
pp. 495-499
Author(s):  
Pavel Ambrož
Keyword(s):  
Magnetic Flux ◽  
Large Scale ◽  
Flux Distribution ◽  
Active Regions ◽  
Giant Cells ◽  
Velocity Fields ◽  
Magnetized Plasma ◽  
Horizontal Flow ◽  
Term Evolution

AbstractLong-term evolution of solar large-scale magnetic fields in relation to the local active phenomena is studied. The changes of the magnetic flux distribution are influenced by the horizontal transport of magnetized plasma. The whole system of magnetic field changes is interpreted as a global process which is controlled by the large-scale convective patterns. The large-scale horizontal velocity field of transporting motions is determined in various approaches with similar results. Regions with positive divergence in the field of horizontal flow field are found to be closely connected with the occurrence of solar active regions. The process of the horizontal flow was analysed by the “cork” method. The corks reveal a pattern of giant cells which are persistent for several solar rotations. These large cells are interpreted as giant convective elements. Occurrence of new strong magnetic flux in regions of positive divergence is then interpreted as a result of emergence of flux in the upflowing parts of that pattern.

scholarly journals Nonequilibrium ionization and ambipolar diffusion in solar magnetic flux emergence processes

2020 ◽  
Vol 633 ◽  
pp. A66 ◽  
Author(s):  
D. Nóbrega-Siverio ◽  
F. Moreno-Insertis ◽  
J. Martínez-Sykora ◽  
M. Carlsson ◽  
M. Szydlarski
Keyword(s):  
Magnetic Flux ◽  
Ambipolar Diffusion ◽  
Solar Interior ◽  
Magnetized Plasma ◽  
Flux Emergence ◽  
Diffusion Term ◽  
Molecule Formation ◽  
Open Questions ◽  
The Impact

Context. Magnetic flux emergence from the solar interior has been shown to be a key mechanism for unleashing a wide variety of phenomena. However, there are still open questions concerning the rise of the magnetized plasma through the atmosphere, mainly in the chromosphere, where the plasma departs from local thermodynamic equilibrium (LTE) and is partially ionized. Aims. We aim to investigate the impact of the nonequilibrium (NEQ) ionization and recombination and molecule formation of hydrogen, as well as ambipolar diffusion, on the dynamics and thermodynamics of the flux emergence process. Methods. Using the radiation-magnetohydrodynamic Bifrost code, we performed 2.5D numerical experiments of magnetic flux emergence from the convection zone up to the corona. The experiments include the NEQ ionization and recombination of atomic hydrogen, the NEQ formation and dissociation of H2 molecules, and the ambipolar diffusion term of the generalized Ohm’s law. Results. Our experiments show that the LTE assumption substantially underestimates the ionization fraction in most of the emerged region, leading to an artificial increase in the ambipolar diffusion and, therefore, in the heating and temperatures as compared to those found when taking the NEQ effects on the hydrogen ion population into account. We see that LTE also overestimates the number density of H2 molecules within the emerged region, thus mistakenly magnifying the exothermic contribution of the H2 molecule formation to the thermal energy during the flux emergence process. We find that the ambipolar diffusion does not significantly affect the amount of total unsigned emerged magnetic flux, but it is important in the shocks that cross the emerged region, heating the plasma on characteristic times ranging from 0.1 to 100 s. We also briefly discuss the importance of including elements heavier than hydrogen in the equation of state so as not to overestimate the role of ambipolar diffusion in the atmosphere.

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