Design of HCN laser based interferometer on the Space Plasma Environment Research Facility (SPERF)

Abstract

A single-channel far-infrared (FIR) hydrogen cyanide (HCN) laser interferometer will be constructed aiming to provide the line integrated electron density on the Space Plasma Environment Research Facility (SPERF) . A continuous glow discharge HCN laser with a cavity length of 3 m is used as the laser source with a wavelength of 337 μm and an output power about 10 mW . The interferometer system is a Mach-Zehnder type. The temporal resolution of the system is 0.1 ms since the phase modulation is achieved by a rotating grating with a modulation frequency of 10 kHz. The beat signal is detected by AlGaN/GaN high electron mobility transistors (HEMT) detector. It has a noise equivalent power of 10 pW/Hz−1/2. Excellent port access (1500×150 mm) and high laser power would promise a profile measurement across the whole plasma section with good signal quality. The design and structure of the single-channel FIR HCN laser interferometer in SPERF is described in detail.

Conceptual design of the tail research experiment at the Space Plasma Environment Research Facility (SPERF-TREX)

“…SPERF is built to provide international platforms of a multifunction scientific research facility for space and plasma physics, including the AREX to study asymmetric reconnection dynamics relevant to coupling between interplanetary and magnetospheric plasmas [32,35,37,38], and DREX to study the transportation characteristics of energetic particles in dipole-like magnetic field configurations [33,34,[36][37][38][39][40]. Meanwhile, TREX mainly investigates: (i) 3D magnetic reconnection of the magnetosphere plasmas, especially in the magnetotail region; (ii) propagation of BBFs in the magnetotail and excitation of hydromagnetic waves; (iii) formation and propagation processes of dipolarization fronts and related spatial environmental effects; and (iv) the injection process of energetic particles into the radiation belt.…”

“…Therefore, ground laboratories have been designed and built to simulate relevant space plasma processes by making use of scaling relations between experiments and the terrestrial space to realize controllable, repeatable, and global simultaneous measurements [30,31]. With reference to the basic parameters of geospace physics, the Space Plasma Environment Research Facility (SPERF) was proposed and designed for the study of magnetosphere processes, such as plasma wave generation and propagation, particle acceleration and transport, magnetic field reconfigurations by three-dimensional magnetic reconnection and dipolarization [32][33][34][35][36][37][38][39][40].…”

“…The SPERF is a key component of the Space Environment Simulation Research Infrastructure (SESRI), a major national science and technology infrastructure for fundamental research. It consists of three research sections: the Asymmetric Reconnection EXperiment (AREX) [32,35,37,38], the Dipole Research EXperiment (DREX) [33,34,[36][37][38][39][40], and the Tail Research EXperiment (TREX) [38], for simulat-ing magnetopause, radiation belt, and magnetotail regions, respectively.…”

Development of a combined interferometer using millimeter wave solid state source and a far infrared laser on ENN’s XuanLong-50 (EXL-50)

“…HCN laser is a gas laser with a resonant cavity length of 3 m, the operating substance is a mixture of nitrogen, methane and hydrogen gas with a ratio of N 2 :CH 4 :H 2 =1:1:5 [8]. HCN laser is electrically excited continuous wave laser, the output power is more than 10 mW at a wavelength of 337 μm for the EH 11 mode [9]. The solid-state diode source output power is above 10 mW in 340 GHz band, original input frequency is in Lo 1 =10.6 GHz band, 32 times frequency doubling, oscillator frequency within 12 MHz is continuously adjustable, frequency modulation step is better than 32±3 kHz, differential frequency drift between two solid-state sources is less than±100 kHz.…”