scholarly journals Higher-order modes in the APS storage ring waveguides

2002 ◽  
Author(s):  
S.O. Brauer ◽  
R.L. Kustom
Keyword(s):  
Storage Ring ◽  
Higher Order ◽  
Higher Order Modes

RF system of the SPring-8 storage ring

1998 ◽  
Vol 5 (3) ◽  
pp. 379-381
Author(s):  
Hiroyasu Ego ◽  
Masahiro Hara ◽  
Yoshitaka Kawashima ◽  
Yuji Ohashi ◽  
Takashi Ohshima ◽  
...  
Keyword(s):  
Storage Ring ◽  
Cooling Water ◽  
Higher Order ◽  
Synchrotron Radiation Beam ◽  
Order Mode ◽  
Coupling Impedance ◽  
Radiation Beam ◽  
Rf System ◽  
Higher Order Modes ◽  
Cavity Cooling

Construction of three RF stations in the storage ring of SPring-8 has been completed. The design concept concentrates on avoiding a coupled-bunch instability which limits the stored current or makes the synchrotron radiation beam unstable. The cavity is bell-shaped to reduce the coupling impedance of the higher-order modes. The cavity dimensions are trimmed systematically to distribute the higher-order mode frequencies. Each cavity has two movable tuners. The temperature of the cavity cooling water is controlled within 0.02 K and the water flow is kept constant. The construction and commissioning of the SPring-8 storage ring RF system is reported.

Installation of new damped cavities at the Photon Factory storage ring

1998 ◽  
Vol 5 (3) ◽  
pp. 369-371 ◽  
Author(s):  
Masaaki Izawa ◽  
Tadashi Koseki ◽  
Shyogo Sakanaka ◽  
Takeshi Takahashi ◽  
Klaus Hass ◽  
...  
Keyword(s):  
Single Cell ◽  
Storage Ring ◽  
High Power ◽  
Simple Structure ◽  
Power Input ◽  
Higher Order ◽  
Microwave Absorber ◽  
Photon Factory ◽  
Higher Order Modes ◽  
Cell Cavity

New damped cavities have been installed in the Photon Factory (PF) storage ring and successfully operated in the last scheduled user run of 1996. The new damped cavity is a simple single-cell cavity with somewhat large beam-duct holes. The part of the beam duct that is attached to the cavity is made of SiC, which works as a microwave absorber and damps the higher-order modes excited in the cavity. Because of its simple structure, the operation of the cavity is very stable and also a high power input of more than 150 kW is possible. No coupled-bunch instabilities due to the new cavity were observed during operation.

scholarly journals Electrical characterisation of higher order spin wave modes in vortex-based magnetic tunnel junctions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alex. S. Jenkins ◽  
Lara San Emeterio Alvarez ◽  
Samh Memshawy ◽  
Paolo Bortolotti ◽  
Vincent Cros ◽  
...  
Keyword(s):  
Spin Wave ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Higher Order ◽  
Spin Torque ◽  
Micromagnetic Simulations ◽  
Higher Order Modes ◽  
Spin Diode ◽  
Super High Frequency ◽  
Wave Modes

AbstractNiFe-based vortex spin-torque nano-oscillators (STNO) have been shown to be rich dynamic systems which can operate as efficient frequency generators and detectors, but with a limitation in frequency determined by the gyrotropic frequency, typically sub-GHz. In this report, we present a detailed analysis of the nature of the higher order spin wave modes which exist in the Super High Frequency range (3–30 GHz). This is achieved via micromagnetic simulations and electrical characterisation in magnetic tunnel junctions, both directly via the spin-diode effect and indirectly via the measurement of the coupling with the gyrotropic critical current. The excitation mechanism and spatial profile of the modes are shown to have a complex dependence on the vortex core position. Additionally, the inter-mode coupling between the fundamental gyrotropic mode and the higher order modes is shown to reduce or enhance the effective damping depending upon the sense of propagation of the confined spin wave.

scholarly journals Design of large mode area all-solid anti-resonant fiber for high-power lasers

2021 ◽  
Vol 9 ◽  
Author(s):  
Xin Zhang ◽  
Shoufei Gao ◽  
Yingying Wang ◽  
Wei Ding ◽  
Pu Wang
Keyword(s):  
High Power ◽  
Single Mode ◽  
Higher Order ◽  
Coupling Scheme ◽  
Resonant Coupling ◽  
Higher Order Modes ◽  
Mode Loss ◽  
Fiber Mode ◽  
Power Needs ◽  
Mode Area

Abstract High-power fiber lasers have experienced a dramatic development over the last decade. Further increasing the output power needs an upscaling of the fiber mode area, while maintaining a single-mode output. Here, we propose an all-solid anti-resonant fiber (ARF) structure, which ensures single-mode operation in broadband by resonantly coupling higher-order modes into the cladding. A series of fibers with core sizes ranging from 40 to 100 μm are proposed exhibiting maximum mode area exceeding 5000 μm2. Numerical simulations show this resonant coupling scheme provides a higher-order mode (mainly TE01, TM01, and HE21) suppression ratio of more than 20 dB, while keeping the fundamental mode loss lower than 1 dB/m. The proposed structure also exhibits high tolerance for core index depression.

On the higher-order modes in rectangular-groove guide

1996 ◽  
Vol 17 (11) ◽  
pp. 1957-1967 ◽  
Author(s):  
W. M. Shi ◽  
K. F. Tsang ◽  
C. N. Wong ◽  
W. X. Zhang
Keyword(s):  
Higher Order ◽  
Higher Order Modes ◽  
Groove Guide ◽  
Rectangular Groove
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