The instability of low-frequency longitudinal modes in strongly coupled dusty plasmas with an ion flow is investigated.The dust charging relaxation is taken into account.It is found that when the ion flow is strong en...The instability of low-frequency longitudinal modes in strongly coupled dusty plasmas with an ion flow is investigated.The dust charging relaxation is taken into account.It is found that when the ion flow is strong enough,the suppression,even disappearence,of instability can occur.Similar to that of the real frequency of waves,the imaginary part of waves also exhibits a transition,which arises from the sensitive dependences on the system parameters and their competition.展开更多
Real-time time-dependent density functional theory(TDDFT)is presently the most accurate available method for computing electronic stopping powers from first principles.However,obtaining application-relevant results of...Real-time time-dependent density functional theory(TDDFT)is presently the most accurate available method for computing electronic stopping powers from first principles.However,obtaining application-relevant results often involves either costly averages over multiple calculations or ad hoc selection of a representative ion trajectory.We consider a broadly applicable,quantitative metric for evaluating and optimizing trajectories in this context.This methodology enables rigorous analysis of the failure modes of various common trajectory choices in crystalline materials.Although randomly selecting trajectories is common practice in stopping power calculations in solids,we show that nearly 30%of random trajectories in an FCC aluminum crystal will not representatively sample the material over the time and length scales feasibly simulated with TDDFT,and unrepresentative choices incur errors of up to 60%.We also show that finite-size effects depend on ion trajectory via“ouroboros”effects beyond the prevailing plasmon-based interpretation,and we propose a cost-reducing scheme to obtain converged results even when expensive core-electron contributions preclude large supercells.This work helps to mitigate poorly controlled approximations in first-principles stopping power calculations,allowing 1–2 order of magnitude cost reductions for obtaining representatively averaged and converged results.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos.19905001 and 59977007the Special Funds for Major State Basic Research Project.
文摘The instability of low-frequency longitudinal modes in strongly coupled dusty plasmas with an ion flow is investigated.The dust charging relaxation is taken into account.It is found that when the ion flow is strong enough,the suppression,even disappearence,of instability can occur.Similar to that of the real frequency of waves,the imaginary part of waves also exhibits a transition,which arises from the sensitive dependences on the system parameters and their competition.
基金AK,ADB,and SBH were partially supported by the US Department of Energy Science Campaign 1.SBH and TWH were partially supported by the US Department of Energy,Office of Science Early Career Research Program,Office of Fusion Energy Sciences under Grant No.FWP-14-017426All authors were partially supported by Sandia National Laboratories’Laboratory Directed Research and Development(LDRD)Project No.218456.
文摘Real-time time-dependent density functional theory(TDDFT)is presently the most accurate available method for computing electronic stopping powers from first principles.However,obtaining application-relevant results often involves either costly averages over multiple calculations or ad hoc selection of a representative ion trajectory.We consider a broadly applicable,quantitative metric for evaluating and optimizing trajectories in this context.This methodology enables rigorous analysis of the failure modes of various common trajectory choices in crystalline materials.Although randomly selecting trajectories is common practice in stopping power calculations in solids,we show that nearly 30%of random trajectories in an FCC aluminum crystal will not representatively sample the material over the time and length scales feasibly simulated with TDDFT,and unrepresentative choices incur errors of up to 60%.We also show that finite-size effects depend on ion trajectory via“ouroboros”effects beyond the prevailing plasmon-based interpretation,and we propose a cost-reducing scheme to obtain converged results even when expensive core-electron contributions preclude large supercells.This work helps to mitigate poorly controlled approximations in first-principles stopping power calculations,allowing 1–2 order of magnitude cost reductions for obtaining representatively averaged and converged results.
