Deuterium retention on the tungsten-coated divertor tiles of JET ITER-like wall in 2015-2016 campaign

Tungsten-coated divertor files exposed during the third JET ITER-Like Wall (ILW) campaign in 2015-2016 (ILW-3) were studied with Secondary Ion Mass Spectrometry (SIMS). ILW-3 campaign contained more high-power plasma discharges and longer plasma time than the earlier ILW campaigns. Measurements showed increased beryllium (Be) deposition on the upper inner divertor, whereas on the outer divertor, Be deposition was lower than during the second campaign in 2013-2014 (ILW-2). Increased intensifies of nickel, molybdenum and tungsten were observed at the surface layer of the inner divertor Be dominated deposits. These layers are probably formed during the high-power plasma discharge phase near the end of the ILW-3 campaign. Compared to the earlier campaigns, D retention on the upper inner divertor was observed to on a similar level than after ILW-2, whereas at the lower inner divertor and most parts of the outer divertor, D retention was lower for ILW-3 than ILW-2. D retention was increased at lower part of outer divertor Tile 7, where Be deposition was slightly increased. Probable reason for the reduction is the higher surface temperature of the files due to higher powers used.Peer reviewe

ENTRAP and its potential interaction with European networks

AbstractENTRAP comprises a pan-European cooperation of leading scientific institutions and regulatory bodies in the field of nuclear-waste characterization and its quality assurance for the safe disposal of radioactive waste. Here, the scope of this cooperation is presented and explained and links or interfaces for a potential collaboration with partners fulfilling tasks of IDG-TP are pursued

Overview of the JET ITER-like wall divertor

The work presented draws on new analysis of components removed following the second JET ITER-like wall campaign 2013–14 concentrating on the upper inner divertor, inner and outer divertor corners, lifetime issues relating to tungsten coatings on JET carbon fibre composite divertor tiles and dust/particulate generation. The results show that the upper inner divertor remains the region of highest deposition in the JET-ILW. Variations in plasma configurations between the first and second campaign have altered material migration to the corners of the inner and outer divertor. Net deposition is shown to be beneficial in the sense that it reduces W coating erosion, covers small areas of exposed carbon surfaces and even encapsulates particles.The work presented draws on new analysis of components removed following the second JET ITER-like wall campaign 2013–14 concentrating on the upper inner divertor, inner and outer divertor corners, lifetime issues relating to tungsten coatings on JET carbon fibre composite divertor tiles and dust/particulate generation. The results show that the upper inner divertor remains the region of highest deposition in the JET-ILW. Variations in plasma configurations between the first and second campaign have altered material migration to the corners of the inner and outer divertor. Net deposition is shown to be beneficial in the sense that it reduces W coating erosion, covers small areas of exposed carbon surfaces and even encapsulates particles.Peer reviewe

KOMERSIALISASI PENDIDIKAN DI ERA GLOBALISASI (Studi Kasus tentang Persepsi Masyarakat terhadap Kuasa Modal dalam Dunia Pendidikan di Kelurahan Jebres, Kecamatan Jebres, Surakarta tahun 2011)

Dwi Hartini. K8407021. KOMERSIALISASI PENDIDIKAN DI ERA GLOBALISASI (Studi Kasus Tentang Persepsi Masyarakat terhadap Kuasa Modal dalam Dunia Pendidikan di Kelurahan Jebres, Surakarta). Skripsi Surakarta: Fakultas Keguruan dan IImu Pendidikan. Universitas Sebelas Maret. 2011. Penelitian ini bertujuan untuk (1) Mengetahui komersialisasi pendidikan yang terjadi di era globalisasi, (2) Mengetahui dampak adanya komersialisasi pendidikan di era globalisasi masyarakat, (3) Mengetahui upaya yang dilakukan masyarakat dalam menghadapi komersialisasi pendidikan yang terjadi di era globalisasi. Penelitian ini menggunakan metode pendekatan kualitatif dengan studi kasus tunggal terpancang. Sumber data dari informan atau narasumber, peristiwa atau aktivitas, dokumen dan arsip serta studi pustaka. Teknik cuplikan menggunakan purposive sampling. Pengumpulan data menggunakan observasi berperan pasif, wawancara dan dokumentasi. Validitas data menggunakan trianggulasi data (sumber) dan metode. Teknik analisis data yang digunakan adalah metode analisis interaktif. Berdasarkan hasil penelitian, dapat disimpulkan 1) Komersialisasi pendidikan yang terjadi di era globalisasi yaitu (a) biaya pendidikan mahal, (b) banyaknya pungutan-pungutan lembaga pendidikan, (c) perdagangan di dunia pendidikan. 2) Dampak positif adanya komersialisasi pendidikan di era globalisasi bagi masyarakat yaitu (a) beban pemerintah membiayai pendidikan semakin berkurang, (b) lembaga pendidikan semakin kompetitif sehingga meningkatkan fasilitas dan mutu pendidikan, (c) menambah keuntungan dan pemasukan kas lembaga pendidikan, sedangkan dampak negatifnya yaitu (a) pendidikan semakin mahal (b) pendidikan sebagai ladang bisnis, (c) gejala stigmatisasi dan diskriminasi antara kaya dan miskin, (d) rantai kemiskinan yang sulit diputuskan melalui pendidikan, (e) tercipta privatisasi pendidikan, (f) sistem suap atau politik uang (money politics) semakin banyak, (g) memacu gaya hidup “besar pasak daripada tiang”, (h) perubahan misi pendidikan dari budaya akademik menjadi budaya ekonomi. 3) Upaya yang dilakukan masyarakat dalam menghadapi komersialisasi pendidikan di era globalisasi yaitu (a) pasrah dengan keadaan seperti pepatah Jawa ”setiap anak membawa rejeki sendiri-sendiri”, (b) memanfaatkan kemajuan teknologi untuk meminimalisir pengeluaran, (c) Pendidikan mahal serta keuangan keluarga yang minim memaksa masyarakat untuk meminjam dana dari bank atau orang lain bahkan menggadaikan atau menjual barang berharga, (d) Kerja keras untuk menambah pendapatan, (e) mengikuti program asuransi maupun tabungan pendidikan, (f) bagi pemerintah seharusnya memperbesar anggaran untuk membantu pendidikan

RF sheath modeling of experimentally observed plasma surface interactions with the JET ITER-Like Antenna

Waves in the Ion Cyclotron Range of Frequencies (ICRF) enhance local Plasma-Surface Interactions (PSI) near the wave launchers and magnetically-connected objects via Radio-Frequency (RF) sheath rectification. ITER will use 20MW of ICRF power over long pulses, questioning the long-term impact of RF-enhanced localized erosion on the lifetime of its Beryllium (Be) wall. Recent dedicated ICRF-heated L-mode discharges documented this process on JET for different types of ICRF antennas. Using visible spectroscopy in JET ICRF-heated L-mode discharges, poloidally-localized regions of enhanced (by similar to 2-4x) Be I and Be II light emission were observed on two outboard limiters magnetically connected to the bottom of the active ITER-Like Antenna (ILA). The observed RF-PSI induced by the ILA was qualitatively comparable to that induced by the JET standard, type-A2 antennas, for similar strap toroidal phasing and connection geometries. The Be II line emission was found more intense when powering the bottom half of the ILA rather than its top half. Conversely, more pronounced SOL density modifications were observed with only top array operation, on field lines connected to the top half of the ILA. So far the near-field modeling of the ILA with antenna code TOPICA (Torino Polytechnic Ion Cyclotron Antenna), using curved antenna model, was partially able to reproduce qualitatively the observed phenomena. A quantitative discrepancy persisted between the observed Be source amplification and the calculated, corresponding increases in E-// field at the magnetically connected locations to the ILA when changing from only top to only bottom half antenna operation. This paper revisits these current drive phased and half-ILA powered cases using for the new simulations flat model of the ILA and more realistic antenna feeding to calculate the E-// field maps with TOPICA code. Further, the Self-consistent Sheaths and Waves for Ion Cyclotron Heating Slow Wave (SSWICH-SW) code, which couples slow wave evanescence with DC Scrape-Off Layer (SOL) biasing, is used to estimate the poloidal distribution of rectified RF-sheath Direct Current (DC) potential V-DC in the private SOL between the ILA poloidal limiters. The approach so far was limited to correlating the observed, enhanced emission regions at the remote limiters to the antenna near-electric fields, as calculated by TOPICA. The present approach includes also a model for the rectification of these near-fields in the private SOL of the ILA. With the improved approach, when comparing only top and only bottom half antenna feeding, we obtained good qualitative correlation between all experimental measurements and the calculated local variations in the E-// field and V-DC potential.Peer reviewe

Current Research into Applications of Tomography for Fusion Diagnostics

Retrieving spatial distribution of plasma emissivity from line integrated measurements on tokamaks presents a challenging task due to ill-posedness of the tomography problem and limited number of the lines of sight. Modern methods of plasma tomography therefore implement a-priori information as well as constraints, in particular some form of penalisation of complexity. In this contribution, the current tomography methods under development (Tikhonov regularisation, Bayesian methods and neural networks) are briefly explained taking into account their potential for integration into the fusion reactor diagnostics. In particular, current development of the Minimum Fisher Regularisation method is exemplified with respect to real-time reconstruction capability, combination with spectral unfolding and other prospective tasks.Peer reviewe