scholarly journals Study of ion cyclotron range of frequencies heating characteristics in deuterium plasma in the Large Helical Device

2021 ◽  
Vol 62 (1) ◽  
pp. 016004
Author(s):  
S. Kamio ◽  
K. Saito ◽  
R. Seki ◽  
H. Kasahara ◽  
M. Kanda ◽  
...  
Keyword(s):  
Simple Model ◽  
Emission Rate ◽  
Neutron Emission ◽  
Model Simulation ◽  
Second Harmonic ◽  
Hydrogen Ion ◽  
Deuterium Plasma ◽  
Ion Heating ◽  
Heating Efficiency ◽  
Ion Cyclotron

Abstract The characteristics of ion cyclotron range of frequencies (ICRF) minority ion heating with a hydrogen minority and deuterium majority plasma were studied by ICRF modulation injection experiments in the Large Helical Device (LHD). In recent experiments with deuterium plasma, no significant increase in the neutron emission rate due to ICRF second harmonic deuteron heating was observed. Therefore, in this study, the neutron emission rate was used to refer to the information regarding the thermal ion component. Like the results of the observations of the heating efficiencies at various minority proton ratios, the experimental results showed good agreement with the simple model simulation of ICRF wave absorption. During these experiments, the accelerated minority hydrogen ions were observed by neutral particle analyzers. The counting rates of the energetic particles were higher in the lines of sight passing through the helical ripple than across the magnetic axis, and the counting rate decreased as the minority hydrogen ion ratio increased. The dependence of the minority hydrogen ion ratio on the density of the energetic ions was consistent with the experimentally observed heating efficiencies and simulations. The heating efficiency of ICRF minority ion heating could be well explained by simple model simulation in the LHD deuterium experiment.

scholarly journals Initial Result of Neutron Emission Rate Analysis for Ion Cyclotron Range of Frequency Heated Deuterium Plasmas in LHD

2020 ◽  
Vol 15 (0) ◽  
pp. 1202088-1202088
Author(s):  
Ryosuke SEKI ◽  
Shuji KAMIO ◽  
Hiroshi KASAHARA ◽  
Kenji SAITO ◽  
Tetsuo SEKI ◽  
...  
Keyword(s):  
Emission Rate ◽  
Neutron Emission ◽  
Initial Result ◽  
Rate Analysis ◽  
Ion Cyclotron

scholarly journals Neutron Emission Rate Characteristics of an Electron Cyclotron Heated Large Helical Device Deuterium Plasma

2021 ◽  
Vol 16 (0) ◽  
pp. 2402008-2402008
Author(s):  
Kunihiro OGAWA ◽  
Mitsutaka ISOBE ◽  
Ryosuke SEKI ◽  
Hideo NUGA ◽  
Siriyaporn SANGAROON ◽  
...  
Keyword(s):  
Emission Rate ◽  
Neutron Emission ◽  
Electron Cyclotron ◽  
Deuterium Plasma

scholarly journals Characterization of the New Vertical Neutron Camera Designed for the Low Neutron Emission Rate Plasma in Large Helical Device

2021 ◽  
Vol 16 (0) ◽  
pp. 1402039-1402039
Author(s):  
Siriyaporn SANGAROON ◽  
Kunihiro OGAWA ◽  
Mitsutaka ISOBE ◽  
Yutaka FUJIWARA ◽  
Hiroyuki YAMAGUCHI ◽  
...  
Keyword(s):  
Emission Rate ◽  
Neutron Emission

ABSOLUTE STANDARDIZATION OF RADIOACTIVE NEUTRON SOURCES: II. THE USE OF THE F19(α, n)Na22 REACTION

1959 ◽  
Vol 37 (5) ◽  
pp. 550-556 ◽  
Author(s):  
K. W. Geiger
Keyword(s):  
Nuclear Reactions ◽  
Emission Rate ◽  
Neutron Emission ◽  
National Research Council ◽  
Neutron Output ◽  
Neutron Sources ◽  
Neutron Thermalization ◽  
Γ Rays ◽  
Absolute Standardization ◽  
Good Agreement

Fluorine has only one stable isotope, F19. If neutrons are produced by the F19(α, n)Na22 reaction the neutron output can be calculated from the yield of the resulting radioactive Na22. The growth of Na22 (half-life, 2.58 years) has been measured in a neutron source consisting originally of 1.6 curies Po210 mixed with CaF2 powder. Since Na22 is a positron emitter, discrimination against γ-rays from Po210 and from nuclear reactions could be achieved by detecting the two positron annihilation quanta in coincidence. The Na22 growth has been followed over 20 months and is in agreement with the theoretical growth curve. Comparison with a calibrated Na22 source yielded a neutron emission rate of (10.70 ± 0.25) × 104 sec−1. This resulted in a neutron emission rate of (3.16 ± 0.10) × 106 sec−1 for the Ra-α-Be source of the National Research Council, in good agreement with (3.22 ± 0.05) × 106 sec−1 obtained by a neutron thermalization method.

scholarly journals Ion Heating by Electromagnetic Ion Cyclotron Waves and Magnetosonic Waves in the Earth's Inner Magnetosphere

2019 ◽  
Vol 46 (12) ◽  
pp. 6258-6267 ◽  
Author(s):  
Q. Ma ◽  
W. Li ◽  
C. Yue ◽  
R. M. Thorne ◽  
J. Bortnik ◽  
...  
Keyword(s):  
Ion Heating ◽  
Inner Magnetosphere ◽  
Ion Cyclotron Waves ◽  
Ion Cyclotron ◽  
Electromagnetic Ion Cyclotron Waves

Pre-saddle and pre-scission neutron emission rates in heavy-ion induced fission of 16O +208Pb and 16O +209Bi systems

2019 ◽  
Vol 28 (03) ◽  
pp. 1950013
Author(s):  
Saeed Soheyli ◽  
Morteza Khalil Khalili ◽  
Ghazaaleh Ashrafi
Keyword(s):  
Emission Rate ◽  
Neutron Emission ◽  
Nonlinear Behavior ◽  
Heavy Ion ◽  
Neutron Multiplicity ◽  
Emission Rates ◽  
Reaction Systems ◽  
Initial Excitation ◽  
Induced Fission ◽  
First Time

Whereas there is a slight information on the pre-saddle neutron emission rate and neutron multiplicity, as well as it is impossible to separate the pre-saddle and saddle to scission neutron contributions experimentally, the theoretical studies of pre-saddle neutron emission rate and neutron multiplicity are of great importance. In the present work, the calculations of pre-saddle neutron multiplicity are performed using the analysis of fission fragment angular anisotropy data for [Formula: see text] and [Formula: see text] reaction systems. The obtained results show that the pre-saddle neutron multiplicity decreases by increasing the initial excitation energy and it has found to be characterized by a nonlinear behavior. Through the analysis of pre-saddle neutron multiplicity and pre-saddle transition time by means of the neutron clock method, the pre-saddle neutron emission rate is calculated for the first time. The findings of this study show that the pre-scission neutron emission rate is lower than the pre-saddle neutron emission rate.

Ion Heating and High-Energy-Particle Production by Ion-Cyclotron Heating in the Large Helical Device

2000 ◽  
Vol 85 (21) ◽  
pp. 4530-4533 ◽  
Author(s):  
T. Mutoh ◽  
R. Kumazawa ◽  
T. Seki ◽  
T. Watari ◽  
K. Saito ◽  
...  
Keyword(s):  
Particle Production ◽  
High Energy ◽  
High Energy Particle ◽  
Energy Particle ◽  
Ion Heating ◽  
Ion Cyclotron

Ion beam excitation of ion-cyclotron waves and ion heating in plasmas with drifting ions

1978 ◽  
Vol 19 (2) ◽  
pp. 237-252 ◽  
Author(s):  
J. P. Hauck ◽  
H. Böhmer ◽  
N. Rynn ◽  
Gregory Benford
Keyword(s):  
Magnetic Field ◽  
Ion Beam ◽  
Ion Beams ◽  
Ion Heating ◽  
Ion Cyclotron Waves ◽  
Diffusion Effects ◽  
Ion Cyclotron ◽  
Cyclotron Mode ◽  
The Magnetic Field ◽  
Beam Excitation

Ion-cyclotron waves are excited by cesium and potassium ion beams in cesium and potassium Q-machine plasmas. The ion beams are injected along the magnetic field with care to avoid beam transverse velocities. The observed ion-cyclotron mode frequencies are below those driven by electron currents. These resonant instabilities are convective in character with small spatial growth rates ki/kr ≃ 0.05. Plasma ion heating is observed and is consistent with a model in which mode amplitudes are saturated by diffusion effects.

scholarly journals A top-down assessment using OMI NO2 suggests an underestimate in the NOx emissions inventory in Seoul, South Korea during KORUS-AQ

2018 ◽  
Author(s):  
Daniel L. Goldberg ◽  
Pablo E. Saide ◽  
Lok N. Lamsal ◽  
Benjamin de Foy ◽  
Zifeng Lu ◽  
...  
Keyword(s):  
South Korea ◽  
Emission Rate ◽  
Model Simulation ◽  
Nox Emission ◽  
Metropolitan Region ◽  
Nox Emissions ◽  
Top Down ◽  
Bottom Up ◽  
Field Campaign ◽  
Emissions Inventory

Abstract. In this work, we investigate the NOx emissions inventory in Seoul, South Korea using a regional NASA Ozone Monitoring Instrument (OMI) NO2 product. We first develop a regional OMI NO2 product by re-calculating the air mass factors using a high-resolution (4 × 4 km2) WRF-Chem model simulation, which better captures the NO2 shape profiles in urban regions. We then apply a model-derived spatial averaging kernel to further downscale the retrieval and account for the sub-pixel variability. These two modifications yield OMI NO2 values in the regional product that are 1.37 larger in the Seoul metropolitan region and > 2 times larger near large industrial sources. These two modifications also yield an OMI NO2 product that is in better agreement with the Pandora NO2 spectrometer measurements acquired during the Korea U.S.-Air Quality (KORUS-AQ) field campaign. NOx emissions are then derived for the Seoul metropolitan area during the KORUS-AQ field campaign using a top-down approach with the standard and regional NASA OMI NO2 products. We first apply the top-down approach to a model simulation to ensure that the method is appropriate: the WRF-Chem simulation utilizing the bottom-up emission inventory yields a NOx emission rate of 227 ± 94 kton/yr, while the bottom-up inventory itself yields a NOx emission rate of 198 kton/yr. Using the top-down approach on the regional OM NO2 product, we derive the NOx emissions rate from Seoul to be 484 ± 201 kton/yr, and a 353 ± 146 kton/yr NOx emissions rate using the standard NASA OMI NO2 product. This suggests an underestimate of 53 % and 36 % using the regional and standard NASA OMI NO2 products respectively. To supplement this finding, we compare the NO2 simulated by WRF-Chem to observations of the same quantity acquired by aircraft and find a model underestimate. When NOx emissions in the WRF-Chem model are doubled, there is better agreement with KORUS-AQ aircraft observations. Although the current work is focused on South Korea using OMI, the methodology developed in this work can be applied to other world regions using TROPOMI and future satellite datasets (e.g., GEMS and TEMPO) to produce high-quality region-specific top-down NOx emission estimates.

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