scholarly journals SITAEL HC1 Low-Current Hollow Cathode

Aerospace ◽  
2020 ◽  
Vol 7 (7) ◽  
pp. 96
Author(s):  
Daniela Pedrini ◽  
Cosimo Ducci ◽  
Ugo Cesari ◽  
Tommaso Misuri ◽  
Mariano Andrenucci
Keyword(s):  
Research And Development ◽  
Hollow Cathode ◽  
Electric Propulsion ◽  
Hall Thruster ◽  
Development Phase ◽  
Hall Thrusters ◽  
Orbit Transfer ◽  
Small Satellites ◽  
Future Developments ◽  
Effective Choice

SITAEL is active in the field of electric propulsion and is involved in the development of different thruster technologies—mainly Hall thrusters (HTs)—of power levels ranging from 100 W up to 20 kW. Low-power HTs are the most effective choice to perform orbit transfer, drag compensation, and de-orbiting maneuvers for small satellites. This paper is dedicated to the activities regarding HC1, the hollow cathode conceived for the 100-W-class Hall thruster under development at SITAEL. Successful test campaigns were performed and are described, with emphasis on the improvements in the cathode design after an extensive research and development phase. The results are presented and discussed, along with future developments of the ongoing activities.

scholarly journals Numerical Investigations of Electromagnetic Oscillations and Turbulences in Hall Thrusters Using Two Fluid Approach

2021 ◽  
Author(s):  
Sukhmander Singh ◽  
Bhavna Vidhani ◽  
Ashish Tyagi
Keyword(s):  
Magnetic Field ◽  
Electric Propulsion ◽  
Specific Impulse ◽  
Magnetized Plasma ◽  
Hall Thruster ◽  
Electron Drift ◽  
Hall Thrusters ◽  
Numerical Investigations ◽  
Electromagnetic Oscillations ◽  
Two Fluid

The first part of the contributed chapter discuss the overview of electric propulsion technology and its requirement in different space missions. The technical terms specific impulse and thrust are explained with their relation to exhaust velocity. The shortcoming of the Hall thrusters and its erosion problems of the channel walls are also conveyed. The second part of the chapter discuss the various waves and electromagnetic instabilities propagating in a Hall thruster magnetized plasma. The dispersion relation for the azimuthal growing waves is derived analytically with the help of magnetohydrodynamics theory. It is depicted that the growth rate of the instability increases with magnetic field, electron drift velocity and collisional frequency, whereas it is decreases with the initial drift of the ions.

scholarly journals Introduction to Plasma Based Propulsion System: Hall Thrusters

2021 ◽  
Author(s):  
Sukhmander Singh ◽  
Sanjeev Kumar ◽  
Shravan Kumar Meena ◽  
Sujit Kumar Saini
Keyword(s):  
Electric Propulsion ◽  
Low Earth Orbit ◽  
Current Status ◽  
Earth Orbit ◽  
Hall Thrusters ◽  
Small Satellite ◽  
Propulsion Systems ◽  
Small Satellites ◽  
Long Time ◽  
The Cost

Technically, there are two types of propulsion systems namely chemical and electric depending on the sources of the fuel. Electrostatic thrusters are used for launching small satellites in low earth orbit which are capable to provide thrust for long time intervals. These thrusters consume less fuel compared to chemical propulsion systems. Therefore for the cost reduction interests, space scientists are interested to develop thrusters based on electric propulsion technology. This chapter is intended to serve as a general overview of the technology of electric propulsion (EP) and its applications. Plasma based electric propulsion technology used for space missions with regard to the spacecraft station keeping, rephrasing and orbit topping applications. Typical thrusters have a lifespan of 10,000 h and produce thrust of 0.1–1 N. These devices have E→×B→ configurations which is used to confine electrons, increasing the electron residence time and allowing more ionization in the channel. Almost 2500 satellites have been launched into orbit till 2020. For example, the ESA SMART-1 mission (Small Mission for Advanced Research in Technology) used a Hall thruster to escape Earth orbit and reach the moon with a small satellite that weighed 367 kg. These satellites carrying small Hall thrusters for orbital corrections in space as thrust is needed to compensate for various ambient forces including atmospheric drag and radiation pressure. The chapter outlines the electric propulsion thruster systems and technologies and their shortcomings. Moreover, the current status of potential research to improve the electric propulsion systems for small satellite has been discussed.

Extended channel Hall thruster for air-breathing electric propulsion

2021 ◽  
Vol 130 (5) ◽  
pp. 053306
Author(s):  
Francesco Marchioni ◽  
Mark A. Cappelli
Keyword(s):  
Electric Propulsion ◽  
Hall Thruster ◽  
Air Breathing

scholarly journals Numerical and Experimental Investigation of Longitudinal Oscillations in Hall Thrusters

Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 148
Author(s):  
Vittorio Giannetti ◽  
Manuel Martín Saravia ◽  
Luca Leporini ◽  
Simone Camarri ◽  
Tommaso Andreussi
Keyword(s):  
Discharge Current ◽  
Fluid Model ◽  
Low Frequency ◽  
Hall Thruster ◽  
Hall Thrusters ◽  
Current Signal ◽  
Plasma Parameters ◽  
Plasma Properties ◽  
Breathing Mode ◽  
Spatio Temporal

One of the main oscillatory modes found ubiquitously in Hall thrusters is the so-called breathing mode. This is recognized as a relatively low-frequency (10–30 kHz), longitudinal oscillation of the discharge current and plasma parameters. In this paper, we present a synergic experimental and numerical investigation of the breathing mode in a 5 kW-class Hall thruster. To this aim, we propose the use of an informed 1D fully-fluid model to provide augmented data with respect to available experimental measurements. The experimental data consists of two datasets, i.e., the discharge current signal and the local near-plume plasma properties measured at high-frequency with a fast-diving triple Langmuir probe. The model is calibrated on the discharge current signal and its accuracy is assessed by comparing predictions against the available measurements of the near-plume plasma properties. It is shown that the model can be calibrated using the discharge current signal, which is easy to measure, and that, once calibrated, it can predict with reasonable accuracy the spatio-temporal distributions of the plasma properties, which would be difficult to measure or estimate otherwise. Finally, we describe how the augmented data obtained through the combination of experiments and calibrated model can provide insight into the breathing mode oscillations and the evolution of plasma properties.

scholarly journals Coupling plasma plume of a low-power magnetically shielded Hall thruster with a hollow cathode

2020 ◽  
Author(s):  
Guangchuan ZHANG ◽  
Junxue REN ◽  
Wei LIANG ◽  
Ning OUYANG ◽  
Chao LU ◽  
...  
Keyword(s):  
Low Power ◽  
Hollow Cathode ◽  
Plasma Plume ◽  
Hall Thruster

Resistive MHD modes in hollow cathodes external plasma

2021 ◽  
Author(s):  
Giulia Becatti ◽  
Francesco Burgalassi ◽  
Fabrizio Paganucci ◽  
Matteo Zuin ◽  
Dan M Goebel
Keyword(s):  
Magnetic Field ◽  
Hollow Cathode ◽  
Electric Propulsion ◽  
Axial Magnetic Field ◽  
Mhd Equations ◽  
Linear Perturbation ◽  
Plasma Parameters ◽  
Hollow Cathodes ◽  
Plume Region ◽  
Helical Mode

Abstract A significant number of plasma instabilities occur in the region just outside of hollow cathodes, depending on the injected gas flow, the current level and the application of an external magnetic field. In particular, the presence of an axial magnetic field induces a helical mode, affecting all the plasma parameters and the total current transported by the plasma. To explore the onset and behavior of this helical mode, the fluctuations in the plasma parameters in the current-carrying plume outside of a hollow cathode discharge have been investigated. The hollow cathode was operated at a current of 25 A, and at variable levels of propellant flow rate and applied magnetic fields. Electromagnetic probes were used to measure the electromagnetic fluctuations, and correlation analysis between each of the probe signals provided spatial-temporal characterization of the generated waves. Time-averaged plasma parameters, such as plasma potential and ion energy distribution function, were also collected in the near-cathode plume region by means of scanning emissive probe and retarding potential analyzer. The results show that the helical mode exists in the cathode plume at sufficiently high applied magnetic field, and is characterized by the presence of a finite electromagnetic component in the axial direction, detectable at discharge currents $\geq$ 25 A. A theoretical analysis of this mode reveals that one possible explanation is consistent with the hypotheses of resistive magnetohydrodynamics, which predicts the presence of helical modes in the forms of resistive kink. The analysis has been carried out by linear perturbation of the resistive MHD equations, from which it is possible to obtain the dispersion relation of the mode and find the $k-\omega$ unstable branch associated with the instability. These findings provided the basis for more detailed investigation of resistive MHD modes and their effect in the plume of hollow cathodes developed for electric propulsion application.

scholarly journals VALIDITAS LEMBAR KERJA PESERTA DIDIK (LKPD) BERBASIS DISCOVERY LEARNING PADA MATERI BANGUN DATAR SEGIEMPAT DI KELAS VII SMP NEGERI 1 BENGKULU TENGAH

2019 ◽  
Vol 3 (2) ◽  
pp. 162-171
Author(s):  
Yulia Rachmawati ◽  
Syafdi Maizora ◽  
Della Maulidiya
Keyword(s):  
Research And Development ◽  
Discovery Learning ◽  
Average Score ◽  
Development Phase ◽  
Design And Development

ABSTRAKPenelitian ini bertujuan untuk menghasilkan Lembar Kerja Peserta Didik (LKPD) berbasis Discovery Learning pada Materi Bangun Datar Segiempat di Kelas VII SMP Negeri 1 Bengkulu Tengah yang memenuhi kriteria valid, praktis, dan efektif. Jenis penelitian ini adalah penelitian pengembangan (research and development) dengan mengadopsi prosedur Four-D (4D) yang dimodifikasi menjadi 3D yaitu tahap define (pendefinisian) design (perancangan)  dan develop (pengembangan) yang terdiri dari uji validitas. Instrumen yang digunakan adalah lembar validasi yang terdiri dari lembar validasi materi, lembar validasi kontruksi dan lembar validasi bahasa. Hasil penelitian menunjukkan bahwa LKPD berbasis Discovery Learning pada Materi Bangun Datar Segiempat di Kelas VII SMP Negeri 1 Bengkulu Tengah termasuk dalam kategori  sangat valid dari segi materi berdasarkan sebelas aspek yang dinilai, valid dari segi kontruksi berdasarkan sepuluh aspek yang dinilai dan valid dari segi bahasa berdasarkan enam aspek yang dinilai dengan skor rata-rata 4,48.Kata Kunci: Validitas, Lembar Kerja Peserta Didik, Discovery Learning ABSTRACTThis research aimed to produce student’s worksheets Based Discovery Learning on Dimentional Figure Rectangular Material at grade VII SMP Negeri 1 Bengkulu Tengah that are valid, practical and effective category. This research was a research and development by adopting procedure of four-D (4D) which was modified into 3D namely define, design, and development phase consisting of validity. Validity instrument were sheet of material sheet, construction sheet, and language sheet. The result of the research showed that LKPD Based Discovery Learning on Dimentional Figure Rectangular Material at  grade VII SMP Negeri 1 Bengkulu Tengah was included in the category being very valid in the eleven aspects of material, being very valid in the ten aspets construction, and being very valid in the six aspects language with average score 4,48Keywords: Validity, student’s Worksheet , Discovery Learning

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