A universal mechanism for plasma blob formation

2019 ◽  
Vol 26 (2) ◽  
pp. 020701 ◽  
Author(s):  
N. Bisai ◽  
Santanu Banerjee ◽  
Abhijit Sen
2021 ◽  
Author(s):  
Nirmal Bisai ◽  
Santanu Banerjee ◽  
Stewart Zweben ◽  
Abhijit Sen

Abstract Abstract Anomalous plasma transport in the boundary region of a tokamak plasma is commonly associated with the formation and evolution of coherent density structures known as blobs. Recently, a theory for a universal mechanism of plasma blob formation has been put forward. It is based on a breaking process of a radially elongated streamer due to poloidal and radial velocity shears. The theory is well supported by two-dimensional and three-dimensional numerical simulation results but lacks experimental validation. In this work, we report the first ever experimental validation of this universal criterion by testing it against NSTX data on blobs obtained using the gas-puff imaging (GPI) diagnostic. It is found that the criterion is widely satisfied in most L-mode discharges and may explain the significantly larger number of blob events. We also validate the theoretical criterion against ADITYA Langmuir probe data taken in the scrape-off layer region.


Author(s):  
L. I. Goncharova ◽  
P. N. Tsygvintsev ◽  
О. А. Guseva

The effect of increased UV-A radiation during the ontogeny of barley plants of the Vladimir variety in the vegetation experiment was studied. Changes in the content of malonic dialdehyde, flavonoids and grain yield were revealed. UV-A radiation as compared to UV-B radiation, has lower quantum energy and can have both positive and negative effects on plant regulatory and photosynthetic processes. One of the most damaging effects of increased levels of UV-A radiation is oxidative stress, which causes lipid peroxidation of biological membranes. The existence of a plant cell in such conditions is possible only thanks to a system of antioxidant defense mechanisms. The accumulation of phenolic compounds under the action of UV radiation is a universal mechanism of protection against photodamage, which was formed in the early stages of the evolution of photoautotrophic organisms. Flavonoids are localized in the epidermis of plant tissues and act as an internal filter. The content of flavonoids is determined by the genotype and due to ontogenetic patterns. Plants were grown in a greenhouse, in vessels containing 4.5 kg of air-dry soil. The repetition is threefold (3 vessels in each variant). Sowing density - 13 plants in each vessel. As a source of UV-A radiation used lamps Black Light BLUE company Philips. Plants were irradiated for 5 hours a day from 10 to 15 hours at 13, 25, 34, 43 and 52 stages of organogenesis. The magnitude of the daily biologically effective dose of UV-A radiation was 60.7 kJ / m2. The solar part of the UV spectrum in the vegetation experiment was absent in the greenhouse. The nature of changes in the content of flavonoids under the action of UV-A irradiation during the growing season of plants with the dynamics of the oxidative process has been established. The first maximum was observed during the vegetative growth period, the second - at the earing stage. The data obtained indicate that flavonoids have ontogenetic conditionality and perform photoprotective functions. The increase in their content under the action of UV-A radiation is accompanied by an increase in resistance to photodamage, which is confirmed by the formation of grain yield.


2019 ◽  
Vol 14 (3) ◽  
pp. 163-175
Author(s):  
Dmitry POGORELOV ◽  
Alexander RODIKOV ◽  
Roman KOVALEV

2020 ◽  
Vol 1 (2) ◽  
pp. 17-27
Author(s):  
Damir R. Salikhov

“Regulatory sandboxes” are regarded as a special mechanism for setting up experimental regulation in the area of digital innovation (especially in financial technologies), creating a special regime for a limited number of participants and for a limited time.Russiahas its own method of experimental regulation, which is not typical but may be helpful for other jurisdictions. There are three approaches to legal experiments (including digital innovations) inRussia. The first approach is accepting special regulation on different issues. There are recent examples of special laws (e.g. Federal Law on the experiment with artificial intelligence technologies inMoscow). An alternative to this option is establishing experimental regulation by an act of the Government if legislation does not prohibit it (e.g. labeling with means of identification). The second approach deals only with Fintech innovations and provides a special mechanism to pilot models of innovative financial technologies. The participants of such a “sandbox” may create a close-to-life model in order to estimate the effects and risks. If the model works fine, the regulation may be amended. The third approach works with creating a universal mechanism of real-life experiments in the sphere of digital innovations based on the special Federal Law and the specific decision of the Government of theRussian Federationor the Bank of Russia in the financial sphere. The author compares the three approaches and their implementation within the framework of Russian legislation and practice and concludes that this experience may be used by developing countries with inflexible regulation, in order to facilitate the development of digital innovations.


Author(s):  
N C Sasini ◽  
R Paikaray ◽  
G S Sahoo

This paper presents the recombination coefficient of the plasma blob is calculated by measuring the electron density ne of the order of 1018m-3 and time (~μs) to move a particular distance.A washer stacked plasma gun is designed to produce high density plasma blob which is moving with speed~104 m/s. As the blob moves radially outward the particle density as well as drift velocity of the blob decreases. Since both charged and neutral components are present in the blob, the recombination may play a dominant role for the blob motion. It has been observed that the recombination co-efficient α (~ 10 -12 m3 s-1) is almost constant across radial distance from gun mouth and in that spatial length the electron-excited molecular collisional ionization is negligible, so two body recombination is dominant.


2018 ◽  
Vol 54 (14) ◽  
pp. 1738-1741 ◽  
Author(s):  
Samuel Askin ◽  
Thomas E. H. Bond ◽  
Alanna E. Sorenson ◽  
Morgane J. J. Moreau ◽  
Helma Antony ◽  
...  

Selective protein unfolding was combined with high-throughput differential scanning fluorimetry of GFP-tagged proteins for the identification of irreversible enzyme inhibitors.


2018 ◽  
Vol 25 (1) ◽  
pp. 012315 ◽  
Author(s):  
R. Häcker ◽  
G. Fuchert ◽  
D. Carralero ◽  
P. Manz
Keyword(s):  

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