Abstract
Renewed interest in active experiments with relativistic particle beams in space has led to the development of solid-state radio-frequency (RF) linear accelerators (linac) that can deliver MeV electron beams but operate with low-voltage DC power supplies. The solid-state RF amplifiers used to drive the accelerator are known as high-electron mobility transistors (HEMTs), and at C-band (5-6 GHz) are capable of generating up to 500 watts of RF power at 10% duty factor in a small package, i.e., the size of a postage stamp. In operation, the HEMTs are powered with 50V DC as their bias voltage; they thus can tap into the spacecraft batteries or electrical bus as the primary power source. In this paper we describe the initial testing of a compact space-borne RF accelerator consisting of individual C-band cavities, each independently powered by a gallium nitride (GaN) HEMT. We show preliminary test results that demonstrate the beam acceleration in a single C-band cavity powered by a single HEMT operating at 10% duty factor. An example of active beam experiments in space that could benefit from the HEMT-powered accelerators is the proposed Magnetosphere-Ionosphere Connection (CONNEX) experiment [Dors et al., 2017].
Highlights
The interconnection between the magnetosphere and the ionosphere has been a topic of intense research for decades
The first round of active beam experiments in space in the 1970s used one of these direct current (DC) electron generators mounted on a sounding rocket to inject a low-energy, high-current electron beam into the ionosphere to study the interaction of electron beam with the nearby and distant magnetosphere (Hendrickson et al, 1975, 1976; Winckler et al, 1975)
Many of these early experiments were performed with lowvoltage, high-current electron beams in the ionosphere where the positive charge left on the spacecraft after the emission of electrons, known as spacecraft charging, was neutralized by the return current from the surrounding plasma
Summary
The interconnection between the magnetosphere and the ionosphere has been a topic of intense research for decades. The CONNEX proposal seeks to answer these questions and establish an unambiguous connection between the magnetosphere and ionosphere through an active mapping technique using relativistic electron beams with beam energy of about 1 MeV (Dors et al, 2017). Such an experiment will be the first of its kind to use high-energy, MeV electron beams as an active probe for doing space science. Electron beams for space experiments have previously used direct current (DC) electrostatic accelerators to deliver electron beam pulses at beam energy up to 40 keV using standard highvoltage DC power supplies These DC electron generators are simple to design and very efficient. The average power consumption during a 4-h engagement is only about 500 W
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
