Journal of the Korean Physical Society最新文献_第8页

Comparison of turbulence and transport characteristics between global flux-driven and gradient-driven gyrofluid simulations in tokamak plasmas 托卡马克等离子体中全球通量驱动和梯度驱动的陀螺流体模拟的湍流和输运特性比较

IF 1 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-23 DOI: 10.1007/s40042-026-01609-5

S. H. Ko, S. S. Kim, Juhyung Kim

{"title":"Comparison of turbulence and transport characteristics between global flux-driven and gradient-driven gyrofluid simulations in tokamak plasmas","authors":"S. H. Ko, S. S. Kim, Juhyung Kim","doi":"10.1007/s40042-026-01609-5","DOIUrl":"10.1007/s40042-026-01609-5","url":null,"abstract":"<div>We perform global nonlinear simulations of ion temperature gradient (ITG) turbulence in a concentric circular tokamak geometry with the gyrofluid code GF2-BOUT++ and compare the dynamics between flux-driven and gradient-driven global simulations. Both approaches present broad 1/f-type power spectra for the turbulent ion heat flux, indicative of self-organized criticality (SOC)-like transport avalanches. Despite the similar levels of the total ion heat fluxes, the two approaches yield markedly different normalized ITG length ((R_0/L_{T_i})). This discrepancy is attributed to differences in turbulence characteristics and low-frequency (varvec{E}times varvec{B}) flow shear. In the flux-driven simulations, mesoscale heat transport is prominent, and the system self-organizes toward a marginally stable state through enhanced mesoscale avalanche-like transport, leading to a lower average temperature gradient than in the gradient-driven case. Strong and persistent (varvec{E}times varvec{B}) shear in the gradient-driven simulations sustains the same heat flux at higher (R_0/L_{T_i}) than in the flux-driven ones. The combined effects of these mechanisms cause (R_0/L_{T_i}) in the flux-driven case to remain near the critical value of approximately 6, which is comparable to full-f gyrokinetic results, and lead to stronger profile stiffness compared to the gradient-driven case.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 1","pages":"78 - 90"},"PeriodicalIF":1.0,"publicationDate":"2026-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148262002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparison of SCAN + U and r2SCAN + U for charge density wave instability and lattice dynamics in CuTe 扫描+ U和r2SCAN + U对cu中电荷密度波不稳定性和晶格动力学的比较

IF 1 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-19 DOI: 10.1007/s40042-026-01622-8

Seungha Ju, Sooran Kim

{"title":"Comparison of SCAN + U and r2SCAN + U for charge density wave instability and lattice dynamics in CuTe","authors":"Seungha Ju, Sooran Kim","doi":"10.1007/s40042-026-01622-8","DOIUrl":"10.1007/s40042-026-01622-8","url":null,"abstract":"<div>Identifying an appropriate exchange–correlation functional and computational conditions is essential for explaining the fundamental physics of materials and predicting their properties. Here, we investigate the performance of the meta-GGA functionals SCAN and r2SCAN, with and without a Hubbard U, for describing the charge density wave (CDW) in the quasi-one-dimensional material CuTe. By examining the Te–Te bond modulation, phonon dispersions, and electronic structures, we identify clear differences in how the two functionals capture the structural and dynamical properties of the CDW formation. r2SCAN + U reproduces the experimentally observed Te-chain distortions in the CDW phase and the phonon soft mode at qCDW = (0.4, 0.0, 0.5) in the non-CDW phase, whereas SCAN exhibits unphysical phonon behavior. The atomic displacements of the soft mode agree well with the experimental Te modulation. Despite their similar electronic structures and optimized lattice constants, our results demonstrate that r2SCAN is a more suitable choice than SCAN for describing CDW formation and lattice dynamics in CuTe.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 1","pages":"12 - 18"},"PeriodicalIF":1.0,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40042-026-01622-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148261921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Beam profile monitor for PAL-XFEL PAL-XFEL光束轮廓监视器

IF 1 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-18 DOI: 10.1007/s40042-026-01607-7

Gyujin Kim, Bongi Oh, Haeryong Yang, Heung-Sik Kang, In Soo Ko, Changbum Kim, Chul Hoon Kim

引用次数: 0

Performance enhancement of AlGaN/GaN HEMTs using ferroelectric spacer integration and neural network modeling 利用铁电间隔集成和神经网络建模增强AlGaN/GaN hemt的性能

IF 0.9 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-18 DOI: 10.1007/s40042-026-01619-3

K. Vinothkumar, R. Mohan Raj

{"title":"Performance enhancement of AlGaN/GaN HEMTs using ferroelectric spacer integration and neural network modeling","authors":"K. Vinothkumar, R. Mohan Raj","doi":"10.1007/s40042-026-01619-3","DOIUrl":"10.1007/s40042-026-01619-3","url":null,"abstract":"<div>AlGaN/GaN High Electron Mobility Transistors (HEMTs) are essential for high-power and high-frequency electronics; nonetheless, challenges, such as short-channel effects, inadequate gate control, and leakage currents, persist, hindering their scalability. This work presents a novel ferroelectric-spacer (FE-spacer) AlGaN/GaN HEMT architecture, which incorporates a ferroelectric Hf₀.₅Zr₀.₅O₂ layer positioned between the gate and the AlGaN barrier. The proposed design aims to improve electrostatic control and enhance Two-Dimensional Electron Gas (2DEG) confinement while maintaining the integrity of the gate stack. This device undergoes analysis through calibrated Sentaurus TCAD simulations and a compact artificial neural network (C-ANN) that has been trained on over 4000 datasets for predictive modeling. The proposed FE-spacer HEMT demonstrates a 35% increase in drain current (Ion = 7.12 × 10⁻4 A), a 45% enhancement in transconductance (gm = 2.47 mS/mm), and a 30% rise in cutoff frequency (fT = 21.5 GHz) relative to conventional HEMTs, along with a further 20% improvement over non-ferroelectric HfO₂ spacer devices. The threshold voltage (Vth) is determined from the linear and saturation regions, yielding values of 0.311 V and 0.275 V, respectively. The Subthreshold Slope (SS) attains a value of 68.57 mV/dec in the linear region, nearing the theoretical limit of 60 mV/dec at 300 K, whereas DIBL exhibits a reduction of 18%. The C-ANN model attains a R2 value exceeding 0.995, effectively predicting various performance parameters while requiring minimal computational resources. The results indicate that the incorporation of a ferroelectric spacer offers a scalable and fabrication-compatible method to improve both DC and RF characteristics of GaN-based HEMTs. Additionally, machine learning facilitates efficient and precise design optimization for advanced high-frequency, low-power applications.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"88 12","pages":"1389 - 1408"},"PeriodicalIF":0.9,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148193826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of external magnetic field on the excitation of lower hybrid wave by beating of two different profile laser beams in spherical nanoparticles 外磁场对两种不同型态激光束在球形纳米颗粒中激发低杂化波的影响

IF 1 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-18 DOI: 10.1007/s40042-026-01620-w

Umesh Kumar Tiwari, Asfiya Ansari, M. S. Patel, Abhimanyu Yadav, S. P. Mishra, Arvind Kumar, Asheel Kumar, Ashish Varma

{"title":"Influence of external magnetic field on the excitation of lower hybrid wave by beating of two different profile laser beams in spherical nanoparticles","authors":"Umesh Kumar Tiwari, Asfiya Ansari, M. S. Patel, Abhimanyu Yadav, S. P. Mishra, Arvind Kumar, Asheel Kumar, Ashish Varma","doi":"10.1007/s40042-026-01620-w","DOIUrl":"10.1007/s40042-026-01620-w","url":null,"abstract":"<div>Herein, we report an analytical theoretical model to excite the electrostatic lower hybrid wave from the nonlinear (counterpropagating) interaction of Hermite cosh-Gaussian and cosh-Gaussian laser beams in collisional magnetized plasma embedded with spherical nanoparticles. As the counterpropagating laser beams interact with this materialistic medium, beat wave generation process takes into the consideration. The spatial field of each laser beam ionized the atoms of spherical nanoparticle and eventually converted it into the plasma plume balls. The beating of two laser beams produces nonlinear ponderomotive to the electronic cloud of nanoplasma. It has much potential to drive the pre-existed electrostatic space charge field and couple the electrostatic lower hybrid wave. The resonant coupling of electrostatic lower hybrid wave is observed as the beat wave frequency of two laser beams approaches near the (1/sqrt{3}) times the electron plasmons frequency. The power amplitude of electrostatic lower hybrid wave is strongly dependent on laser beams parameter (laser beam width, beam decentered parameter, and Hermite polynomial mode index) and medium parameter (electron–ion collisional frequency, electron cyclotron frequency, spherical nano particle radii, and interparticle separation). The applied static magnetic field enhances the electrostatic wave excitation and controls the coupling. This electrostatic wave excitation theory might be applicable in enhanced laser absorption, charged particle acceleration, electron heating, and high harmonic generation process.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 1","pages":"62 - 77"},"PeriodicalIF":1.0,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148261871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental performance evaluation of prototype single-spoke resonator superconducting RF cavities 原型单辐谐振腔超导射频腔的实验性能评价

IF 1 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-16 DOI: 10.1007/s40042-026-01617-5

Heetae Kim, Sungmin Jeon, Juwan Kim

引用次数: 0

The QCD scale parameter from the photon structure function 从光子结构函数得到QCD尺度参数

IF 0.9 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-16 DOI: 10.1007/s40042-026-01605-9

Hun Jang, Eun Bok, Hyeunwoo Kim, Byeongjun Yoon, Sun Myong Kim

引用次数: 0

Microwave instability study in a high-current electron storage ring 大电流电子存储环中的微波不稳定性研究

IF 1 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-16 DOI: 10.1007/s40042-026-01592-x

Weijie Fan, Ji Li, Yanxu Wang, Chao Feng, Qinglei Zhang, Demin Zhou

{"title":"Microwave instability study in a high-current electron storage ring","authors":"Weijie Fan, Ji Li, Yanxu Wang, Chao Feng, Qinglei Zhang, Demin Zhou","doi":"10.1007/s40042-026-01592-x","DOIUrl":"10.1007/s40042-026-01592-x","url":null,"abstract":"<div>In modern storage rings, microwave instability frequently represents a critical performance-limiting factor. A storage ring-based coherent light source (SRCLS) generally requires high average current to generate coherent extreme ultraviolet (EUV) radiation, featuring exceptionally strong damping capabilities and high beam current operation. To achieve high average power, this kind of light source maintains beam parameters characterized by high intensity, short bunch length, and a reduced momentum compaction factor, which heightens the significance of microwave instability. Notably, when particles propagate through bending magnets, there are substantially stronger coherent synchrotron radiation (CSR) effects compared to conventional light sources. Furthermore, the implementation of multiple damping wigglers to achieve short damping times produces intense coherent wiggler radiation (CWR). Given these considerations, a thorough investigation of microwave instability becomes imperative. This paper provides a comprehensive characterization of the dominant short-range wake fields in the storage ring and investigates the corresponding microwave instability thresholds.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 on","pages":"292 - 300"},"PeriodicalIF":1.0,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148458788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Phase transitions of a three-dimensional spin-half quantum XXZ model: a quantum Monte Carlo study 三维自旋半量子XXZ模型的相变：量子蒙特卡罗研究

IF 0.9 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-16 DOI: 10.1007/s40042-026-01610-y

Doje Yi, Ji-Woo Lee

引用次数: 0

2D radiative transfer through water curtain using SH and CG methods 利用SH和CG方法进行水幕二维辐射传输

IF 0.9 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2026-03-16 DOI: 10.1007/s40042-026-01612-w

Robertine Kang, Arantes Fokou, Pierre Marie Wakeu Pola, Fabien Kenmogne, Gerard Nfor Junior Bawe, Réné Tchinda

引用次数: 0