Back-diffusion plasma generator for ionosphere study

Abstract

To produce ionospheric plasma environments at ground level is essential to get information not only for the development of CubeSat-class spacecraft but also for the design of ionospheric plasma instruments and to confirm their performance. In this paper, we describe the principle of plasma generation and characteristics of the back-diffusion plasma source, which can produce inlab plasma similar to the Earth's ionosphere, E and F regions, conditions of electron and ion temperature and density. The ion and electron energy distributions of the plasma generated by a back-diffusion source are measured by means of a cleaned Langmuir probe and gridded particle energy analyzers. The ion motion in front of the source is investigated by a hard-sphere collision model in SIMION software and the simulation results are comparable with the findings of our experiment. Furthermore, plasma densities and ion temperatures at different positions in front of the source are also demonstrated. The back-diffusion source has been accommodated for ionospheric plasma productions in several Asian institutes. The plasma characteristics of the source shown in this paper will benefit space research groups in the development of space plasma instruments.

Plasma potential measurements using an emissive probe made of oxide cathode

“…3, we find that the electron emission of the oxide cathode emissive probe is initiated at I ht = 90 mA with a corresponding T of about 1200 K, while the electron emission of the traditional tungsten emissive probe is initiated at I ht = 134 mA with a corresponding T of about 1800 K. Moreover, the oxide cathode emissive probe and the traditional tungsten emissive probe can produce an appreciable electron emission with T equal 045205-3 to about 1400 K and 2200 K, respectively. The results agree well with the electron emission properties of the tungsten cathode and BaO cathode reported in the published literature, [11,22] indicating that our estimate of T is reliable. The difference between the operating temperature (about 700 K) of the two probes suggests the great advantage of the oxide cathode emissive probe in operating at lower temperature and saving energy.…”

“…With its lower work function, a BaO cathode is often used as an electron source to obtain stable and long-lasting electron emission. [21,22] Note that the oxide cathode coating used here is so thin that it is difficult to see clearly in the photograph. Before the oxide cathode emissive probe was used for the first time it was heated continuously for 10 min with I ht of 120 mA to ensure that the ternary carbonate can be completely decomposed.…”

Reliable measurements of low-density plasmas using a novel Langmuir probe with a guard tube

“…Among space plasmas, the ionosphere, a complex and dynamic region extending from 80 to 1000 km above the Earth's surface, is the most common application of the Langmuir probe [5][6][7][8]. The plasma in the lower ionosphere has a typical electron temperature of 0.05-0.3 eV and a typical electron density of 10 8 -10 12 m −3 [9][10][11]. In laboratories, the Langmuir probe is extensively used to investigate various plasmas with a wide range of electron densities from 10 10 to 10 19 m −3 [12][13][14][15].…”

Plasma parameters and discharge characteristics of lab-based krypton-propelled miniaturized Hall thruster

“…The marked progress in the space industry has largely been catalysed by the increasing capacity and affordability of deployment technology that have made space accessible to industries and moderately sized companies for telecommunications, surveillance, and acquisition and analytics of big data in space [7,8]. As the space industry is no longer a niche field reserved for a privileged few from the military, an extensive set of capabilities are in continuous development for the realization of novel missions [9][10][11]. A good example would be the rapid advancement of small satellite technology [12][13][14].…”