English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

HELicon Experiment for Negative ion source (HELEN-I) with single driver isdeveloped with a focus on the production of negative hydrogen ions. In theHelicon wave heated plasmas, very high plasma densities ($\sim10^{19} m^{-3}$)can be attained with electron temperatures as low as $\sim$1 eV in thedownstream region. These conditions favor the production of negative hydrogenions. In HELEN-I device at IPR, helicon plasma is produced using Hydrogen gasin a diverging magnetic field, created by a permanent ring magnet. RF Power($P_{RF}$) of 800-1000W at 13.56 MHz frequency is applied to a Nagoya-IIIantenna to excite m = 1 helicon mode in the plasma. The plasma is confined by amulti-cusp field configuration in the expansion chamber. The transition frominductively coupled mode to Helicon mode is observed near $P_{RF}$ 700W withplasma density $\sim 10^{18} m^{-3}$ and electron temperature $\sim$ 5 eV inthe driver and $\sim$ 1eV in the expansion volume. Line integrated negativehydrogen ion density is measured in the expansion chamber by employing anOptical Emission Spectroscopy (OES) diagnostic technique using$H_\alpha/H_\beta$ ratio and Laser photo-detachment based Cavity Ring Downspectroscopic (CRDS) diagnostic technique. The measured value of negativehydrogen ion density is in the order of $10^{16} m^{-3}$ at 6 mTorr pressureand does not vary significantly with power in the helicon mode, pressure anddownstream axial magnetic field variation. The negative ion densitymeasurements are compared with theoretically estimated values calculated usingparticle balance method considering different reaction rates responsible fornegative hydrogen ion creation and destruction. It is to be noted that atpresent Caesium (Cs) is not injected in the plasma discharge to enhance $H^-$ion density.

Characterization of hydrogen plasma in a permanent ring magnet based helicon plasma source for negative ion source research