A poloidal high-k scattering system for NSTX-U

A previous 5-channel tangential high-k scattering system is being replaced by an 8-channel, poloidal high-k scattering system on the National Spherical Torus eXperiment Upgrade (NSTX-U) device located in Princeton, NJ, USA. The 693 GHz poloidal scattering system replaces a 280 GHz tangential scattering system to study high-k electron density fluctuations on NSTX-U, thereby considerably enhancing planned turbulence physics studies by providing a measurement of the k θ -spectrum of both electron temperature gradient (ETG) and ion temperature gradient (ITG) modes. Two approaches to generating the 693 GHz probe beam are under development: an optically-pumped far-infrared (FIR) laser that generates ∼50 mW, and a compact gyrotron that can potentially generate in excess of 5 W. Large aperture optics collect radiation scattered from density fluctuations in the plasma core at 8 simultaneous scattering angles ranging from 2 to 15° corresponding to poloidal wavenumbers that extend to >40 cm−1. Steerable launch optics coupled with receiver optics mounted on a 5-axis receiver carriage allow the scattering volume to be placed radially from r/a = 0.3 out to the pedestal region (r/a ∼ 0.99) and translated horizontally as needed to satisfy wavenumber matching.

Teknologi Tanaman Padi Sistem Tanam Benih Langsung dengan Hambur di Dataran Tinggi Sumatera Utara (Studi Kasus di Kabupaten Humbang Hasundutan)

Rice farmers in Humbang Hasundutan Regency still maintain rice technology with the scattering system because farmers feel this planting system to be still relevant to the condition of available resources in Humbang Hasundutan Regency. The study of direct seed planting system technology in Humbang Hasundutan Regency was carried out using a survey method by conducting interviews with key informants in Polung Subdistrict, Humbang Hasundutan Regency. From the interview results, it was found that the transplanting system technology, both with tiles and jajar legowo in Humbang Hasundutan Regency, did not give significantly different results compared to the scattering system. The results of the farming analysis obtained show that the scattering system gives an R/C value of 1.88 compared to the transplanting system of 1.94 R/C.

Influence of optical loss on nonlinear effect in stimulated Raman scattering system

In this paper, based on the ideal stimulated Raman coupling equation, the dynamic output state is investigated. Considering the gain and loss of stimulated Raman scattering in the actual situation, the ideal stimulated Raman coupling equation is modified. Furthermore, the influence of optical loss on the nonlinear effect in the stimulated Raman scattering system has been analyzed. The results show that, considering the gain and loss of the system, the dynamic output of the stimulated Raman coupling equation presents stable periodic oscillation and random oscillation.