scholarly journals Taylor State Merging at SSX: Experiment and Simulation

Plasma ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 27-37
Author(s):  
Michael Brown ◽  
Kaitlin Gelber ◽  
Matiwos Mebratu
Keyword(s):  
Magnetic Reconnection ◽  
Magnetized Plasma ◽  
The Other ◽  
Inertial Fusion ◽  
Ion Heating ◽  
Left Handed ◽  
Suitable Target ◽  
Magnetohydrodynamic Simulations ◽  
Plasma Guns ◽  
Warm State

We describe experiments and simulations of dynamical merging with two Taylor state plasmas in a Swarthmore Spheromak Experiment (SSX) device. Taylor states are formed by magnetized plasma guns at opposite ends of the device. We performed experiments with Taylor states of both senses of magnetic helicity (right-handed twist or left-handed twist). We present results of both counter-helicity merging (one side left-handed, the other right-handed) and co-helicity merging (both sides left-handed). Experiments show significant ion heating, consistent with magnetic reconnection. We suggest that the merged, warm state could be a suitable target for future magneto-inertial fusion experiments. Magnetohydrodynamic simulations of these experiments reveal the structure of the final relaxed, merged state.

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.

Lateral Onset Asynchrony in Left-Handers

1976 ◽  
Vol 43 (1) ◽  
pp. 255-259 ◽  
Author(s):  
Takeshi Hatta
Keyword(s):  
Visual Field ◽  
Standard Stimulus ◽  
The Other ◽  
Right Visual Field ◽  
Left Handed ◽  
The Right ◽  
Onset Asynchrony

Study of matching judgment was designed to demonstrate an effect of lateral onset asynchrony in left-handed subjects, 7 males and 8 females. Japanese Hirakana letters or random forms were presented to one visual field first and to the other visual field second. 15 left-handers were requested to judge whether the successively presented stimuli were “same” or “different.” The results showed that for both types of stimuli there are no differences in accuracy of matching judgment whether the standard stimulus was presented to the right visual field first or to the left. These results indicate that the left-handed subjects may have a tendency toward hemispheric equi-potentiality for recognition of both verbal and non-verbal materials.

Microsurgically generated discontinuities provoke heritable changes in cellular handedness of a ciliate, Stylonychia mytilus

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 337-356
Author(s):  
X.B. Shi ◽  
Z.I. Qiu ◽  
W. He ◽  
J. Frankel
Keyword(s):  
Large Scale ◽  
Mirror Image ◽  
The Other ◽  
Left Edge ◽  
Left Handed ◽  
Specific Manner ◽  
The Right ◽  
Anteroposterior Polarity ◽  
Posterior Anterior ◽  
Stylonychia Mytilus

Stylonychia mytilus is a dorsoventrally flattened ciliate with compound ciliary structures arranged in a specific manner on the cell surface. In mirror-image (MI) doublets of this ciliate, two nearly complete sets of ciliary structures are arrayed side-by-side, one in a normal or ‘right-handed’ (RH) arrangement, the other in a reversed or ‘left-handed’ (LH) arrangement. MI-doublets exist in two forms, one with the RH component on the right, the LH component on the left, and feeding structures near the center (‘buccal-adjoining MI-doublet’); the other with the RH component on the left, the LH component on the right, and feeding structures on the lateral edges (‘buccal-opposing MI-doublet’). We describe an operation that can generate either type of MI-doublet. This operation interchanges large anterior and posterior regions of the cell, transposing the original posterior region anteriorly (P—A) and the original anterior region posteriorly (A—P), while retaining the original anteroposterior polarity of each region. Two sets of new ciliary structures then are formed in mirror-image arrangement, with the set in the P—A region oriented normally and the set in the A—P region undergoing a reversal of polarity along its anteroposterior axis. This sometimes creates end-to-end MI forms, but more commonly produces side-by-side MI-doublets through a folding together of the P—A and A—P regions. This folding occurs because one lateral edge of the cell had been removed during the operation; if the left edge was removed, the complex folds to the left and forms a buccal-adjoining MI-doublet, whereas if the right edge was removed, the complex folds to the right and forms a buccal-opposing MI-doublet. Both types can reorganize and later divide true-to-type, although the ‘buccal-opposing’ type is by far the more stable of the two. The generation of mirror-image forms is dependent on the prior abnormal juxtaposition of regions from opposite ends of the cell, and involves a coordinated respecification of large-scale organization. We interpret this response to be a consequence of intercalation of missing intervening positional values in the zone of posterior-anterior abutment.

Ehud, Stigma, and the Management of Spoiled Identity

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
David J. Chalcraft
Keyword(s):  
Social Stigma ◽  
The Other ◽  
Social Model ◽  
Erving Goffman ◽  
Self Identity ◽  
Social Model Of Disability ◽  
Left Handedness ◽  
Left Handed ◽  
Moral Career ◽  
The One

The story of Ehud, and his assassination of the Moabite King Eglon (Judges 3: 12–30), continues to entertain readers and hearers alike. The story also perplexes, largely on moral grounds. This paper utilises the sociology of Erving Goffman and insights from disability studies to re-tell the story of Ehud as someone who is doubly stigmatised. That is, Ehud not only carriers the stigma of left-handedness but is also disabled; moreover, the Moabite King is also disabled/immobile because of his obesity. I take the biblical text as conveying that Ehud is left-handed by necessity given the impairment in his right hand/arm. Adopting a social model of disability, I apply Goffman’s account of the management of spoiled identity developed in his book Stigma (1963) to explore how the narrative depicts various dimensions of social stigma and Ehud’s moral career as he attempts to manage his spoiled identity and the degrees of societal acceptance and rejection he experiences in different contexts. The key arguments of Goffman are summarised before I apply central concepts from Goffman to the biblical story. Concepts include “moral career,” the distinction between social, personal and ego (self-) identity, and the key distinction between a person with a stigma being discredited (because the impairment is obvious and seen by all), on the one hand, or bearing a stigma that is discreditable (that is, it would discredit them if found out), on the other.

scholarly journals Regimes of magnetic reconnection in colliding laser-produced magnetized plasma bubbles

2018 ◽  
Vol 25 (9) ◽  
pp. 093105 ◽  
Author(s):  
K. V. Lezhnin ◽  
W. Fox ◽  
J. Matteucci ◽  
D. B. Schaeffer ◽  
A. Bhattacharjee ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Magnetized Plasma ◽  
Plasma Bubbles

scholarly journals Density gradient effects on beam plasma linear instabilities for fast ignition scenario

2006 ◽  
Vol 24 (2) ◽  
pp. 269-273 ◽  
Author(s):  
ANTOINE BRET ◽  
CLAUDE DEUTSCH
Keyword(s):  
Electron Beam ◽  
Relativistic Electron ◽  
Density Gradient ◽  
Relativistic Electron Beam ◽  
Fast Ignition ◽  
The Other ◽  
Inertial Fusion ◽  
Linear Phase ◽  
Unstable System ◽  
Gradient Effects

In the fast ignition scenario for inertial fusion, a relativistic electron beam is supposed to travel from the side of the fusion pellet to its core. One one hand, a relativistic electron beam passing through a plasma is a highly unstable system. On the other hand, the pellet core is denser than its side by four orders of magnitude so that the beam makes its way through a important density gradient. We here investigate the effect of this gradient on the instabilities. It is found that they should develop so early that gradient effects are negligible in the linear phase.

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