A large volume plasma device

Abstract

Investigation of highly complex electromagnetic phenomena responsible for fundamental processes in geospace plasma calls for a laboratory device, large enough to provide minimum boundary effects on the electromagnetic waves under concern. The production of large volume, uniform, and quiescent plasma of density ∼1012 cm−3 requires a suitable large area plasma source. The influence of energetic electrons on the phenomena under study can be eliminated using pulsed, highly reproducible discharges so that the afterglow, devoid of energetic electrons, becomes the experimental plasma. Measurement over a large volume with high spatial and temporal resolution, acquisition, and storage of voluminous data form other difficult tasks. The requirement to have tasks of plasma generation, wave excitation, and data acquisition automatically sequenced, also demands a sophisticated control system. A large volume plasma device (LVPD), possessing the following unique features, has been developed in our laboratory: (i) a large area multifilamentary source, (ii) a pulsed power system (width ⩽15 ms and turn off time ≈10 μs), (iii) a three-axes probe drive, (iv) data acquisition and control system with 1 GS/s sampling rate and ≈20 GB memory, and (v) an extended magnet coil system giving desired field profile. The achieved plasma parameters include, ne∼1012 cm−3, Te≈8 eV in the main glow, and ne≈3×1011 cm−3 and Te≈2 eV in the after glow, and plasma uniformity within 5% over 1 m in axial and radial extents. The present article describes the LVPD device.

Electromagnetic Waves and Instabilities in Magnetoplasmas: Ion and Electron Dynamics of Whistler, Alfvén and Drift Waves

“…The influence of boundaries on the dispersion of electromagnetic waves was already theoretically investigated [20,21]. Most experiments circumvented the effect by going to very small wavelengths [22,23] and large-size experiments [24,25].…”

“…This leads to the common whistler wave dispersion relation. Plasma dimensions much larger than λ are usually found in ionospheric plasmas [18], some large sized laboratory experiments [24,25] or if plasma density or wave frequency are high enough to ensure sufficiently small wavelengths [1,22]. A rigorous theoretical treatment of electromagnetic waves in a plasma filled waveguide with axial magnetic field was developed by Uhm and co-workers [21].…”

Electron magneto-hydrodynamic waves bounded by magnetic bubble

“…1, is discussed in detail in earlier reports. 13,15,16 For experiments in the uniform field condition, a set of 10 external magnet coils have been appropriately charged to produce a uniform magnetic field in the range 4-20 G, in the z direction (device axis).…”

“…We have set up an arrangement in the large volume plasma device (LVPD), 13 where the transition region discussed above has been reproduced and has been kept sufficiently large so that a complete dispersive analysis of the waves traversing this region can be carried out. We reproduce the conditions similar to what a propagating wave excited as in Ref.…”

From Electrojet to ITER: India's Journey in Experimental Plasma Physics

“…The Large Volume Plasma Device (LVPD) meets many of these requirements [30]. A 60 cm by 60 cm multi filamentary cathode, produces large volume, quiescent plasma of density 1012 / cm3, with 5% uniformity over 1 m axially and radially.…”