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Title: The Mochi LabJet Experiment for Measurements of Canonical Helicity Injection in a Laboratory Astrophysical Jet

The Mochi device is a new pulsed power plasma experiment designed to produce long, collimated, stable, magnetized plasma jets when set up in the LabJet configuration. The LabJet configuration aims to simulate an astrophysical jet in the laboratory by mimicking an accretion disk threaded by a poloidal magnetic field with concentric planar electrodes in front of a solenoidal coil. The unique setup consists of three electrodes, each with azimuthally symmetric gas slits. Two of the electrodes are biased independently with respect to the third electrode to control the radial electric field profile across the poloidal bias magnetic field. This design approximates a shear azimuthal rotation profile in an accretion disk. The azimuthally symmetric gas slits provide a continuously symmetric mass source at the footpoint of the plasma jet, so any azimuthal rotation of the plasma jet is not hindered by a discrete number of gas holes. The initial set of diagnostics consists of current Rogowski coils, voltage probes, magnetic field probe arrays, an interferometer and ion Doppler spectroscopy, supplemented by a fast ion gauge and a retarding grid energy analyzer. The measured parameters of the first plasmas are ~10 22 m -3, ~0.4 T, and 5–25 eV, with velocities ofmore » ~20–80 km s -1. Finally, the combination of a controllable electric field profile, a flared poloidal magnetic field, and azimuthally symmetric mass sources in the experiment successfully produces short-lived (~10 μs, ≳5 Alfvén times) collimated magnetic jets with a ~10:1 aspect ratio and long-lived (~100 μs, ≳40 Alfvén times) flow-stabilized, collimated, magnetic jets with a ~30:1 aspect ratio.« less
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [2] ;  [2] ;  [2] ;  [2] ;  [2]
  1. Univ. of Washington, Seattle, WA (United States). Aeronautics & Astronautics; Univ. of Tokyo (Japan). Graduate School of Frontier Sciences
  2. Univ. of Washington, Seattle, WA (United States). Aeronautics & Astronautics
Publication Date:
Report Number(s):
Journal ID: ISSN 1538-4365; 894204
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal. Supplement Series (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal. Supplement Series (Online); Journal Volume: 236; Journal Issue: 2; Journal ID: ISSN 1538-4365
American Astronomical Society/IOP
Research Org:
Univ. of Washington, Seattle, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 42 ENGINEERING; galaxies; jets; ISM; outflows; plasmas; stars; winds
OSTI Identifier: