A new pellet injection system has been equipped on the experimental advanced superconducting tokamak（EAST） in the 2012 campaign,with a pellet size of Ф 2 mm×2 mm,a frequency of1 Hz–10 Hz and velocity of 150 m...A new pellet injection system has been equipped on the experimental advanced superconducting tokamak（EAST） in the 2012 campaign,with a pellet size of Ф 2 mm×2 mm,a frequency of1 Hz–10 Hz and velocity of 150 m s^-1–300 m s^-1.The deuterium pellet is well-known for plasma fuelling as well as for triggering the edge localized mode（ELM）.In the 2012 campaign,pellet injection experiments were successfully carried out on EAST.Temporary plasma detachment achieved by deuterium pellets has been observed in a double null（DN） divertor configuration,with multi-pellet injections at a repetition frequency of 2 Hz.The partial detachment of the outer divertors and complete detachment of the inner divertors was achieved after 35 ms of each pellet injection,which have a duration of 30–60 ms with the maximum degree of detachment（DOD） reaching 3.5 and 37,respectively.Meanwhile,the multifaceted asymmetric radiation from the edge（MARFE） phenomena was also observed at the high field side（HFS） near both the lower and upper X-points with radiation loss suddenly increased to about 15%–70%,which may be the main cause of divertor plasma detachment.The temporary detachment induced by pellet injection may act as a new way to study divertor detachment behaviors.展开更多
MARFE phenomena on HT-7 tokamak is studied in this paper. A best correlation' has been found between the total input ohmic power and the product of the .edge line average density and Zeff. MARFEs which is strongly...MARFE phenomena on HT-7 tokamak is studied in this paper. A best correlation' has been found between the total input ohmic power and the product of the .edge line average density and Zeff. MARFEs which is strongly correlated with impurity density, always occurs at Zeff = 3~8 ohmic discharges. In HT-7 tokamak high Zeff discharges, it is found that the MARFEs usually occur at values of : in the range of 0.5~0.7, where p = In the case of good wall condition (Zeff= 1 ~2), the onset of MARFEs have not been observed before reaching the Greenwald density limit' on HT-7. An improved confinement mode plasma which is induced by the MARFE is observed, the global particle confinement time increases 1.9 times. The relaxation time between the MARFE event trigger and the L-U transition is about 1.4 ms, the followed L-H transition time is 1.9 ms, the improved confinement mode phase is maintained for about 40 ms. MARFE cools the plasma edge, and the electron density profileis observed to become more narrow and peaking.展开更多
Multifaceted asymmetric radiation from the edge(MARFE) movement which can cause density limit disruption is often encountered during high density operation on many tokamaks. Therefore, identifying and predicting MARFE...Multifaceted asymmetric radiation from the edge(MARFE) movement which can cause density limit disruption is often encountered during high density operation on many tokamaks. Therefore, identifying and predicting MARFE movement is meaningful to mitigate or avoid density limit disruption for the steady-state high-density plasma operation. A machine learning method named random forest(RF) has been used to predict the MARFE movement based on the density ramp-up experiment in the 2022’s first campaign of Experimental Advanced Superconducting Tokamak(EAST). The RF model shows that besides Greenwald fraction which is the ratio of plasma density and Greenwald density limit, dβp/dt,H98and d Wmhd/dt are relatively important parameters for MARFE-movement prediction. Applying the RF model on test discharges, the test results show that the successful alarm rate for MARFE movement causing density limit disruption reaches ~ 85% with a minimum alarm time of ~ 40 ms and mean alarm time of ~ 700 ms. At the same time, the false alarm rate for non-disruptive and non-density-limit disruptive discharges can be kept below 5%. These results provide a reference to the prediction of MARFE movement in high density plasmas, which can help the avoidance or mitigation of density limit disruption in future fusion reactors.展开更多
Meiosis-arrest female 1（MARF1） is a recently identified key oogenic regulator essential for the maintenance of female fertility and genome integrity in mice. However, the detailed functions and the underlying mechan...Meiosis-arrest female 1（MARF1） is a recently identified key oogenic regulator essential for the maintenance of female fertility and genome integrity in mice. However, the detailed functions and the underlying mechanisms of MARF1 remain elusive. Here, in an attempt to create a mouse model expressing fluorescent protein-tagged MARF1 to facilitate further exploration of the roles of MARF1 in oocytes, we produced a Marf1-eGFP knockin（KI） mouse line in which the C-terminal structure and function of MARF1 were interfered by its fusing eGFP peptide. Using these Marfl-eGFP-KI mice, we revealed, unexpectedly, the functions of MARF1 in the control of oocyte meiotic division.We found that the Marfl-eGFP-KI females ovulated mature oocytes with severe meiotic and developmental defects,and thus were infertile. Moreover, meiotic reinitiation was delayed while meiotic completion was accelerated in the KI-oocytes, which was coincident with the increased incidence of oocyte aneuploidy. Therefore, MARF1 is indispensable for maintaining the fidelity of homolog segregation during oocyte maturation, and this function relies on its C-terminal domains.展开更多
基金supported by National Natural Science Foundation of China(Nos.11575236,11275231,11305206)the National Magnetic Confinement Fusion Science Program of China(Nos.2013GB107003,2014GB106005,2015GB101000)
文摘A new pellet injection system has been equipped on the experimental advanced superconducting tokamak（EAST） in the 2012 campaign,with a pellet size of Ф 2 mm×2 mm,a frequency of1 Hz–10 Hz and velocity of 150 m s^-1–300 m s^-1.The deuterium pellet is well-known for plasma fuelling as well as for triggering the edge localized mode（ELM）.In the 2012 campaign,pellet injection experiments were successfully carried out on EAST.Temporary plasma detachment achieved by deuterium pellets has been observed in a double null（DN） divertor configuration,with multi-pellet injections at a repetition frequency of 2 Hz.The partial detachment of the outer divertors and complete detachment of the inner divertors was achieved after 35 ms of each pellet injection,which have a duration of 30–60 ms with the maximum degree of detachment（DOD） reaching 3.5 and 37,respectively.Meanwhile,the multifaceted asymmetric radiation from the edge（MARFE） phenomena was also observed at the high field side（HFS） near both the lower and upper X-points with radiation loss suddenly increased to about 15%–70%,which may be the main cause of divertor plasma detachment.The temporary detachment induced by pellet injection may act as a new way to study divertor detachment behaviors.
文摘MARFE phenomena on HT-7 tokamak is studied in this paper. A best correlation' has been found between the total input ohmic power and the product of the .edge line average density and Zeff. MARFEs which is strongly correlated with impurity density, always occurs at Zeff = 3~8 ohmic discharges. In HT-7 tokamak high Zeff discharges, it is found that the MARFEs usually occur at values of : in the range of 0.5~0.7, where p = In the case of good wall condition (Zeff= 1 ~2), the onset of MARFEs have not been observed before reaching the Greenwald density limit' on HT-7. An improved confinement mode plasma which is induced by the MARFE is observed, the global particle confinement time increases 1.9 times. The relaxation time between the MARFE event trigger and the L-U transition is about 1.4 ms, the followed L-H transition time is 1.9 ms, the improved confinement mode phase is maintained for about 40 ms. MARFE cools the plasma edge, and the electron density profileis observed to become more narrow and peaking.
基金This work is supported by the National MCF Energy R&D Program of China(Grant Nos.2018YFE0302100 and 2019YFE03010003)the National Natural Science Foundation of China(Grant Nos.12005264,12105322,and 12075285)+3 种基金the National Magnetic Confinement Fusion Science Program of China(Grant No.2022YFE03100003)the Natural Science Foundation of Anhui Province of China(Grant No.2108085QA38)the Chinese Postdoctoral Science Found(Grant No.2021000278)the Presidential Foundation of Hefei institutes of Physical Science(Grant No.YZJJ2021QN12).
文摘Multifaceted asymmetric radiation from the edge(MARFE) movement which can cause density limit disruption is often encountered during high density operation on many tokamaks. Therefore, identifying and predicting MARFE movement is meaningful to mitigate or avoid density limit disruption for the steady-state high-density plasma operation. A machine learning method named random forest(RF) has been used to predict the MARFE movement based on the density ramp-up experiment in the 2022’s first campaign of Experimental Advanced Superconducting Tokamak(EAST). The RF model shows that besides Greenwald fraction which is the ratio of plasma density and Greenwald density limit, dβp/dt,H98and d Wmhd/dt are relatively important parameters for MARFE-movement prediction. Applying the RF model on test discharges, the test results show that the successful alarm rate for MARFE movement causing density limit disruption reaches ~ 85% with a minimum alarm time of ~ 40 ms and mean alarm time of ~ 700 ms. At the same time, the false alarm rate for non-disruptive and non-density-limit disruptive discharges can be kept below 5%. These results provide a reference to the prediction of MARFE movement in high density plasmas, which can help the avoidance or mitigation of density limit disruption in future fusion reactors.
基金supported by National Basic Research Program (973) from Ministry of Science and Technology of the People's Republic of China (grant numbers 2014CB943200, 2013CB945500)National NaturalScience Foundation of China (grant numbers 31471351, 31271538)Natural Science Foundation of Jiangsu Province (grant number BK20140061)to YQ Su
文摘Meiosis-arrest female 1（MARF1） is a recently identified key oogenic regulator essential for the maintenance of female fertility and genome integrity in mice. However, the detailed functions and the underlying mechanisms of MARF1 remain elusive. Here, in an attempt to create a mouse model expressing fluorescent protein-tagged MARF1 to facilitate further exploration of the roles of MARF1 in oocytes, we produced a Marf1-eGFP knockin（KI） mouse line in which the C-terminal structure and function of MARF1 were interfered by its fusing eGFP peptide. Using these Marfl-eGFP-KI mice, we revealed, unexpectedly, the functions of MARF1 in the control of oocyte meiotic division.We found that the Marfl-eGFP-KI females ovulated mature oocytes with severe meiotic and developmental defects,and thus were infertile. Moreover, meiotic reinitiation was delayed while meiotic completion was accelerated in the KI-oocytes, which was coincident with the increased incidence of oocyte aneuploidy. Therefore, MARF1 is indispensable for maintaining the fidelity of homolog segregation during oocyte maturation, and this function relies on its C-terminal domains.
