The global distribution properties of Ultra Low Frequency wave (ULF) in the inner magnetospgere and its interactions with energetic particles, such as the wave-particle resonance, modulation, and particle acceleration...The global distribution properties of Ultra Low Frequency wave (ULF) in the inner magnetospgere and its interactions with energetic particles, such as the wave-particle resonance, modulation, and particle acceleration, are active topics in space physics research. These problems are fundamentally important issues to understand the energy transport from the solar wind into the magnetosphere. In this paper we briefly reviewed the recent research progress on ULF wave and its interactions with energetic particles in the inner magnetosphere; furthermore, we suggested some open questions for future study.展开更多
We suggest a scheme of electron acceleration by use of two tightly focused ultra-short intense laser pulses at a IOOTW level. Electroas obtain a preliminary acceleration with a small angular spread by the longitudinal...We suggest a scheme of electron acceleration by use of two tightly focused ultra-short intense laser pulses at a IOOTW level. Electroas obtain a preliminary acceleration with a small angular spread by the longitudinal ponderomotive force of the first pulse. They are then injected and further accelerated to hundreds of MeV by the second laser pulse.展开更多
太阳高能粒子事件常伴随太阳耀斑和日冕物质抛射事件(Coronal Mass Ejections,CME)出现,由于太阳高能粒子事件的关键因素是双CME的相互作用,利用SOHO卫星观测的高能粒子强度、耀斑强度以及CME的相对高度与时间,通过高度与时间拟合得到...太阳高能粒子事件常伴随太阳耀斑和日冕物质抛射事件(Coronal Mass Ejections,CME)出现,由于太阳高能粒子事件的关键因素是双CME的相互作用,利用SOHO卫星观测的高能粒子强度、耀斑强度以及CME的相对高度与时间,通过高度与时间拟合得到的速度,分析了2001年4月15日和2005年1月20日的太阳高能粒子事件强度与相关双CME事件的关系,发现这两个太阳高能粒子事件中E≥10 MeV质子的强度与双CME事件无关.因此在这两次太阳高能粒子事件早期,E≥10 MeV质子的强度只与相关太阳耀斑和CME有关.展开更多
为解决现有各种基因枪在微弹制备方面存在的问题并减小冲击波影响,提出一种基因枪结构。将裹着基因疫苗的微弹吸附在不锈钢网上,并将不锈钢网放置在加速通道中加速微弹。在数值模拟的基础上,研制了实验装置,测试了装置的性能,并利用该...为解决现有各种基因枪在微弹制备方面存在的问题并减小冲击波影响,提出一种基因枪结构。将裹着基因疫苗的微弹吸附在不锈钢网上,并将不锈钢网放置在加速通道中加速微弹。在数值模拟的基础上,研制了实验装置,测试了装置的性能,并利用该装置将pEGFG质粒导入H e la细胞。实验结果表明:这种结构的基因枪在0.3M Pa的气压下就可以把微弹加速到300m/s以上,且微弹在靶面分布均匀;射入H e la细胞的pEGFG质粒也得到了表达,能满足基因疫苗接种的要求。展开更多
采用CFD-DEM(Computational Fluid Dynamics with Discrete Element Method),模拟了磨料射流中颗粒在清水与0.2%(以质量分数计)胍胶溶液中的运动过程,研究了颗粒的运动轨迹、颗粒在喷嘴轴线位置处的速度变化情况、流体参数对射流扩散及...采用CFD-DEM(Computational Fluid Dynamics with Discrete Element Method),模拟了磨料射流中颗粒在清水与0.2%(以质量分数计)胍胶溶液中的运动过程,研究了颗粒的运动轨迹、颗粒在喷嘴轴线位置处的速度变化情况、流体参数对射流扩散及颗粒空间分布的影响。在喷嘴收缩段内,胍胶溶液中的颗粒加速最快;在喷嘴外,随喷射距离的增加,胍胶溶液中心射流的速度衰减较快,清水中颗粒的减速较慢。在射流中心区域,与清水相比,胍胶溶液的射流中心处的颗粒占比相对较少,分布较为分散。研究结果表明,相比清水,胍胶溶液使得颗粒速度的加速更快,颗粒冲击能量更强,辅助钻井破岩的能力更强。展开更多
The Centro de Laseres Pulsados in Salamanca,Spain has recently started operation phase and the first user access period on the 6 J 30 fs 200 TW system(VEGA 2)already started at the beginning of 2018.In this paper we r...The Centro de Laseres Pulsados in Salamanca,Spain has recently started operation phase and the first user access period on the 6 J 30 fs 200 TW system(VEGA 2)already started at the beginning of 2018.In this paper we report on two commissioning experiments recently performed on the VEGA 2 system in preparation for the user campaign.VEGA 2 system has been tested in different configurations depending on the focusing optics and targets used.One configuration(long focal length F=130 cm)is for underdense laser-matter interaction where VEGA 2 is focused onto a low density gas-jet generating electron beams(via laser wake field acceleration mechanism)with maximum energy up to 500 MeV and an X-ray betatron source with a 10 keV critical energy.A second configuration(short focal length F= 40 cm)is for overdense laser-matter interaction where VEGA 2 is focused onto a 5 μm thick Al target generating a proton beam with a maximum energy of 10 MeV and temperature of 2.5 MeV.In this paper we present preliminary experimental results.展开更多
A mixed hydrogen and helium（H ＋ He） spectrum with a clear steepening at ~700 TeV has been detected by the ARGO-YBJ experiments. In this paper, we demonstrate that the observed H ＋ He spectrum can be reproduced wel...A mixed hydrogen and helium（H ＋ He） spectrum with a clear steepening at ~700 TeV has been detected by the ARGO-YBJ experiments. In this paper, we demonstrate that the observed H ＋ He spectrum can be reproduced well with a model of cosmic rays escaping from the supernova remnants（SNRs） in our Galaxy. In this model, particles are accelerated in a SNR through a non-linear diffusive shock acceleration mechanism. Three components of high energy light nuclei escaped from the SNR are considered. It should be noted that the proton spectrum observed by KASCADE can be also explained by this model given a higher acceleration efficiency.展开更多
In this paper, we construct rotating charged hairy black hole in(2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the ...In this paper, we construct rotating charged hairy black hole in(2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the centerof-mass energy of two colliding test particles near the rotating charged hairy black hole in(2+1) dimensions. As we expected, the center-of-mass energy has infinite value.展开更多
This paper describes a model of electron energization and cyclotron-maser emission applicable to astrophysical magnetized collisionless shocks. It is motivated by the work of Begelman, Ergun and Rees [Astrophys. J. 62...This paper describes a model of electron energization and cyclotron-maser emission applicable to astrophysical magnetized collisionless shocks. It is motivated by the work of Begelman, Ergun and Rees [Astrophys. J. 625, 51(2005)] who argued that the cyclotron-maser instability occurs in localized magnetized collisionless shocks such as those expected in blazar jets. We report on recent research carried out to investigate electron acceleration at collisionless shocks and maser radiation associated with the accelerated electrons. We describe how electrons accelerated by lower-hybrid waves at collisionless shocks generate cyclotron-maser radiation when the accelerated electrons move into regions of stronger magnetic fields. The electrons are accelerated along the magnetic field and magnetically compressed leading to the formation of an electron velocity distribution having a horseshoe shape due to conservation of the electron magnetic moment. Under certain conditions the horseshoe electron velocity distribution function is unstable to the cyclotron-maser instability [Bingham and Cairns, Phys. Plasmas 7, 3089(2000); Melrose, Rev. Mod. Plasma Phys. 1, 5(2017)].展开更多
基金the National Natural Science Foundation of China (Grant Nos. 40528005 and 40390152)
文摘The global distribution properties of Ultra Low Frequency wave (ULF) in the inner magnetospgere and its interactions with energetic particles, such as the wave-particle resonance, modulation, and particle acceleration, are active topics in space physics research. These problems are fundamentally important issues to understand the energy transport from the solar wind into the magnetosphere. In this paper we briefly reviewed the recent research progress on ULF wave and its interactions with energetic particles in the inner magnetosphere; furthermore, we suggested some open questions for future study.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10335020, 10105014 and 10390160）, the National High Technology Inertial Confinement Fusion Foundation of China, and the National Key Basic Research Special Foundation of China （Grant No G1999075200）.
文摘We suggest a scheme of electron acceleration by use of two tightly focused ultra-short intense laser pulses at a IOOTW level. Electroas obtain a preliminary acceleration with a small angular spread by the longitudinal ponderomotive force of the first pulse. They are then injected and further accelerated to hundreds of MeV by the second laser pulse.
文摘太阳高能粒子事件常伴随太阳耀斑和日冕物质抛射事件(Coronal Mass Ejections,CME)出现,由于太阳高能粒子事件的关键因素是双CME的相互作用,利用SOHO卫星观测的高能粒子强度、耀斑强度以及CME的相对高度与时间,通过高度与时间拟合得到的速度,分析了2001年4月15日和2005年1月20日的太阳高能粒子事件强度与相关双CME事件的关系,发现这两个太阳高能粒子事件中E≥10 MeV质子的强度与双CME事件无关.因此在这两次太阳高能粒子事件早期,E≥10 MeV质子的强度只与相关太阳耀斑和CME有关.
文摘为解决现有各种基因枪在微弹制备方面存在的问题并减小冲击波影响,提出一种基因枪结构。将裹着基因疫苗的微弹吸附在不锈钢网上,并将不锈钢网放置在加速通道中加速微弹。在数值模拟的基础上,研制了实验装置,测试了装置的性能,并利用该装置将pEGFG质粒导入H e la细胞。实验结果表明:这种结构的基因枪在0.3M Pa的气压下就可以把微弹加速到300m/s以上,且微弹在靶面分布均匀;射入H e la细胞的pEGFG质粒也得到了表达,能满足基因疫苗接种的要求。
文摘采用CFD-DEM(Computational Fluid Dynamics with Discrete Element Method),模拟了磨料射流中颗粒在清水与0.2%(以质量分数计)胍胶溶液中的运动过程,研究了颗粒的运动轨迹、颗粒在喷嘴轴线位置处的速度变化情况、流体参数对射流扩散及颗粒空间分布的影响。在喷嘴收缩段内,胍胶溶液中的颗粒加速最快;在喷嘴外,随喷射距离的增加,胍胶溶液中心射流的速度衰减较快,清水中颗粒的减速较慢。在射流中心区域,与清水相比,胍胶溶液的射流中心处的颗粒占比相对较少,分布较为分散。研究结果表明,相比清水,胍胶溶液使得颗粒速度的加速更快,颗粒冲击能量更强,辅助钻井破岩的能力更强。
基金Support from Spanish Ministerio de Ciencia, Innovacion y Universidades through the PALMA Grant No. FIS2016-81056-RICTS Equipment Grant No. EQC2018005230-P+1 种基金from LaserLab Europe IV Grant No. 654148from Junta de Castilla y Leon Grant No. CLP087U16
文摘The Centro de Laseres Pulsados in Salamanca,Spain has recently started operation phase and the first user access period on the 6 J 30 fs 200 TW system(VEGA 2)already started at the beginning of 2018.In this paper we report on two commissioning experiments recently performed on the VEGA 2 system in preparation for the user campaign.VEGA 2 system has been tested in different configurations depending on the focusing optics and targets used.One configuration(long focal length F=130 cm)is for underdense laser-matter interaction where VEGA 2 is focused onto a low density gas-jet generating electron beams(via laser wake field acceleration mechanism)with maximum energy up to 500 MeV and an X-ray betatron source with a 10 keV critical energy.A second configuration(short focal length F= 40 cm)is for overdense laser-matter interaction where VEGA 2 is focused onto a 5 μm thick Al target generating a proton beam with a maximum energy of 10 MeV and temperature of 2.5 MeV.In this paper we present preliminary experimental results.
基金Supported by the National Natural Science Foundation of China(11433004,11363006,11103016,11173020)Top Talents Program of Yunnan Province(2015HA030)the Natural Science Foundation of Yunnan Province(2015FB103)
文摘A mixed hydrogen and helium（H ＋ He） spectrum with a clear steepening at ~700 TeV has been detected by the ARGO-YBJ experiments. In this paper, we demonstrate that the observed H ＋ He spectrum can be reproduced well with a model of cosmic rays escaping from the supernova remnants（SNRs） in our Galaxy. In this model, particles are accelerated in a SNR through a non-linear diffusive shock acceleration mechanism. Three components of high energy light nuclei escaped from the SNR are considered. It should be noted that the proton spectrum observed by KASCADE can be also explained by this model given a higher acceleration efficiency.
文摘In this paper, we construct rotating charged hairy black hole in(2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the centerof-mass energy of two colliding test particles near the rotating charged hairy black hole in(2+1) dimensions. As we expected, the center-of-mass energy has infinite value.
基金funding from the Engineering and Physical Sciences Research Council(grant Nos.EP/N014472/1,EP/R004773/1and EP/N013298/1)the Science and Technologies Facilities Council of the United Kingdom.F.C.+2 种基金support from the European Research Council(InPairs ERC-2015-AdG 695088)FCT Portugal(grant No.PD/BD/114307/2016)supported in part at the University of Chicago by the US DOE NNSA ASC through the Argonne Institute for Computing in Science under FWP 57789 and the US DOE Office of Science through grant No.DE-SC0016566
文摘This paper describes a model of electron energization and cyclotron-maser emission applicable to astrophysical magnetized collisionless shocks. It is motivated by the work of Begelman, Ergun and Rees [Astrophys. J. 625, 51(2005)] who argued that the cyclotron-maser instability occurs in localized magnetized collisionless shocks such as those expected in blazar jets. We report on recent research carried out to investigate electron acceleration at collisionless shocks and maser radiation associated with the accelerated electrons. We describe how electrons accelerated by lower-hybrid waves at collisionless shocks generate cyclotron-maser radiation when the accelerated electrons move into regions of stronger magnetic fields. The electrons are accelerated along the magnetic field and magnetically compressed leading to the formation of an electron velocity distribution having a horseshoe shape due to conservation of the electron magnetic moment. Under certain conditions the horseshoe electron velocity distribution function is unstable to the cyclotron-maser instability [Bingham and Cairns, Phys. Plasmas 7, 3089(2000); Melrose, Rev. Mod. Plasma Phys. 1, 5(2017)].
