Recent results from studies of electron beam phenomena in space plasmas (original) (raw)
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Radiation from pulsed electron beams in space plasmas
Radio Science, 1984
2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION IAVAILABILITY OF REPORT N/A Approved for publication; distribution 2b. OECLASSIFICATION / DOWNGRADING SCHEDULE unlimited. N/A 4. PERFORMING ORGANIZATION REPORT NUMBER(S) S. MONITORING ORGANIZATION REPORT NUMBER(S) N/A RADC-TR-86-167 64. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION Stanford University (if apcabe) Rome Air Development Center (EEPS) 6€. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (City, State, and ZIP Code) STAR Laboratory Hanscom AFB MA 01731-5000 Stanford CA 94305 Sa. NAME OF FUNDING/SPONSORING Sb_ OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION If applicable) Rome Air Development Center EEPS F19628-84-K-0014 Sc. ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS
Geophysical Research Letters, 1985
Recent rocket and space shuttle experiments have demonstrated the capability to launch electron beams of moderate power (100 W to 10 kW) into the earth's ionosphere and magnetosphere. In this letter we describe how such beams, when fired from rockets or satellites, can create significant ionization in the E and Fregions of the ionosphere. Through proper selection of beam-related parameters, an interesting variety of plasma density structures, including plasma sheets and plasma filaments, can be created and studied over periods of 30 minutes to i hour, depending on the rate of plasma recombination and the density of the ambient plasma. Observations of these structures can give new information relating to the physics of plasma density structures in the ionosphere and the effects these features have upon the scattering of radio waves. It is also possible that observations of the density structures will provide a new means for studying neutral winds and electrodynamic phenomena in the ionosphere.
Space Plasma Physics: A Review
arXiv (Cornell University), 2022
Owing to the ever-present solar wind, our vast solar system is full of plasmas. The turbulent solar wind, together with sporadic solar eruptions, introduces various space plasma processes and phenomena in the solar atmosphere all the way to the Earth's ionosphere and atmosphere and outward to interact with the interstellar media to form the heliopause and termination shock. Remarkable progress has been made in space plasma physics in the last 65 years, mainly due to sophisticated in-situ measurements of plasmas, plasma waves, neutral particles, energetic particles, and dust via space-borne satellite instrumentation. Additionally high technology ground-2 To appear in IEEE Transactions on Plasma Science
VLF wave emissions by pulsed and DC electron beams in space, 1, Spacelab 2 observations
Journal of Geophysical Research, 1988
During the Spacelab 2 space shuttle mission a 1-keV, 100-mA, square-wave-modulated, electron source (FPEG) and a plasma diagnostics subsatellite (PDP) were Used to investigate the properties of radio waves generated bY electron beams in space. A variety of electron beam pulsing sequences were executed to investigate specific properties of the beam-plasma-wave interaction. In addition to operations conduct:ed with the PDP in the payload bay, several investigations were conducted with the PDP operated as a free-flying satellite at distances of several hundred meters from the orbiter. In this paper we present the results of three beam operation sequences which provide new information about the characteristics of wave generation by electron beams. Those sequences are (1) the "DC flux tube connection" sequence in which the FPEG was operated with continuous electron emission while the orbiter maneuvered to connect the PDP and the orbiter on the same magnetic field line; (2) a "Pulsed flux tube connection" sequence for which the electron beam was square-wave-modulated at 1.22 kHz; and (3) a "Prox Ops" sequence in which the FPEG was again pulsed at 1.22 kHz while the PDP was modnted in the orbiter payload bay rather than operating as, afi'ee-fiying satellite. Analysis of the amplitudes of VLF emissions from these FPEG sequences allows comparison of broadband emissions from the dc and pulsed electron beams, comparison of broadband and narrow-band emissions during the pulsed electron beam emissions, and investigation of the production and propagation properties of radio waves generated by dc and pulsed electron beams in space plasmas. Spectrograms showing the general characteristics of the ambient wave environment and the wave environment generated during these three sequences are presented. The results of electron beam-generated wave observations from the STS 3/OSS I mission were verified. Both dc and modulated electron beams produce copious broadband emissions. Square-wave-modulated electron beams produce nan'ow-band radiation at the pulsing frequency and its harmonics along with the broadband emissions. The time evolution and spectral structure of broadband and narrow-band emissions are analyzed. Our observations indicated that dc, 50-mA electron beams and pulsed, 50% duty cycle, 100-mA beams produce broadband radiation which is conaparable in intensity and spectral shape at all points for which the wave field was sampled. Observation of the waves produced by the electron beam during the flux tube connections indicates that there are three zones of wave emissions characterized by the amplitude of waves in those spatial regions. Zone I is a highly disturbed region near the beam with very intense wave activity. Zone 2 is a region of wave activity which decreases rapidly with increasing distance from the beam, and zone 3 contains lower amplitude emissions which appear to be near-field COntributions. The amplitude of narrow-band emissions is in good agreement with the predictions of theory for waves generated through the Cherenkov resonance with wave normal angles less than the resonance cone angle, and the harmonic structure of the narrow-band radiation is found to be dependent on the beam propagation characteristics. li ,INTRODUCTION Since the first experiment with electron beams in space plasmas [Hess, 1969] there has been continued and growing interest in beam-plasma experiments conducted in the Copyright 1988 by the American Geophysical Union Paper number 88JA03596. 0148-0227/88/88JA-03596505.00 ionosphere and magnetosphere. Rocket-borne electron beam experi'-ments ha• been used to investigate a large range of phenomena including propagation of an electron bunch in the magnetosphere [Winckler, 1980], electrical charging of rockets [e.g.,Jacobsen and Maynard, 1980; N. B. Myers et al., CHARGE 2, A sounding rocket payload to investigate vehicle charging effects due to electron beam emissions., submitted to J. Spacecr. Rockets., 1988 ], electric fields at geosynchronous altitudes [Meltzner, 1978], radio wave emission from modulated electron beams [Gendrin, 1974; Holzworth and Koons, 1981; Winckler et al., 1984, 1985], and 14,699 14,700 REEVES ET AL.' VLF YVAVE EMISSIONS BY PULSED AND DC ELECTRON BEAMS the charging and wave generation mechanisms involved in a tethered rocket system [Sasaki et al., 1986a]. The first electron beam experiment to be carricJ on the space shuttle was flown on the March 1982 flight, STS 3, as part of the vehicle charging and potential (VCAP) experiment on the Office of Space Science 1 (OSS 1) mission [Banks et al., 1987]. Cooperative use of a square-wave-•nodulated (1-keV, 50/100-mA) fast pulsed electron generator (FPEG) and the instruments on the University of Iowa plasma. diagnostics package (PDP) permitted numerous observations of the interaction of the electron beam..with the ambient plasma environment in the vicinity of the orbiter. These experiments, because of the relatively long durati'6n of the orbit, could be used to investigate the disturbed plasma environxnent around the orbiter [Shawhah et al., 1984a; Banks et al., 1987], charging of the orbiter during passive conditions and during electron 'beam injection in a variety of plasma environments [Hawkins, 1988], and the production of waves produced by both dc and square-wave-modulated electron beams [Shawhah et al., 1984b; Reeves et al., 1988]. Three shuttle-based electron beam experiments have followed. The Space Experiments with Particle AcCelerators (SEPAC) beam-plasma experiments were flown on the Spacelab 1 mission in 1983. The SEPAC experiments utilized a higher-power electron bealh than the VCAP/PDP (up to 5 keV, 300 mA), a plasma plmne injector, a neutral gas plume injector, a TV camera, and a diagnostics package to investigate the properties of spacecraft charging, neutralization, and return currents for relatively high power electron beams. The SEPAC experiments and results have been reported by Obayashi et al. [1982], Akai [1984], Sasaki [1986b], Cai et al. [1987], ,•nd Neubert et al. [1986a]. The separate phenomena induced by charged particle beams (PICPAB) experiment investigated the radiation produced by operation of the electron beam [Be9hin et al., 1984]. More recent electron beam experiments in space took place on the Spacelab 2 mission in July and August 1985. Spacelab 2 included a reflight of VCAP and the PDP. During this mission the PDP wa.s released a.s•.a free-flying satellite for a period of six hours. During the free flight the orbiter and the PDP completed six Earth orbits while the orbiter maneuvered around the PDP, allowing measurement of the plasma and wave enviromnent out to separations of several hundred meters. Four periods of the•ree flight included carefully planned magnetic flux tube connections in which the orbiter maneuvered into a position such that' it pa•sed through the same geomagnetic field lines as the P DP. Two flux tube connections were used to study the effects of the passive interaction of the orbiter with tile ionosphere, one flux tube connection took place with the FPEG operating i• dc mode with a 50-mA current, and during the final connection the FPEG was pulsed at 1.22 kHz, 100-mA With a duty cycle of 50% (beam on-time equals beam off-time). A total of 325 electron beam pulsing sequences were conducted with the P DP free-flying and •nounted in the payload bay. An overview of the Spacelab 2 mission is forthcoming in the work by P.M. Banks et al. (Results of vehicle charging, plasma densities, and wave generation experi•nents on Spacelab 2, submitted to J. Spacecr. Rockets, 1988; here-14,702 REEVES ET AL.: VLF %VAVE EMISSIONS BY PULSED AND DC ELECTRON BEAMS
One-dimenssional electromagnetic simulation of multiple electron beams propagating in space plasmas
Journal of Geophysical Research, 2010
It is by now well known that electron beams play an important role in generating radio emissions such as type II and type III radio bursts, commonly observed by spacecraft in the interplanetary medium. Electron beams streaming back from Earth's bow shock into the solar wind have been proposed as a possible source for the electron plasma waves observed by spacecraft in the electron foreshock. Recent observations suggest that during the natural evolution of the foreshock plasma, multiple electron beams could be injected over a period of time, losing their individual identity to coalesce into a single beam. In this work, we use an electromagnetic particle-in-cell (PIC) code "KEMPO 1D, adapted" to simulate two electron beams that are injected into a plasma at different times. The first beam disturbs the background plasma and generates Langmuir waves by electron beam-plasma interaction. Subsequently, another beam is inserted into the system and interacts with the first one and with the driven Langmuir waves to produce electromagnetic radiation. The results of our simulation show that the first beam can produce electrostatic harmonics of the plasma frequency, while the second beam intensifies the emission at the harmonics that is produced by the first one. The behavior of the second beam is strongly determined by the preexisting Langmuir wave electric fields. The simulations also show, as a result of the interaction between both beams, a clear nonlinear frequency shift of the harmonic modes as well as an increase of electromagnetic and kinetic energies of the wave-particle system.
Perspectives on Space and Astrophysical Plasma Physics
Symposium - International Astronomical Union
We summarize the discussion of the current status and future prospects of space and astrophysical plasma research prepared by the Panel on Space and Astrophysical plasmas, a part of the study on Physics administered by the National Research Council of the National Academy of Sciences. The Study on Physics is chaired by W. Brinkman of Bell Laboratories and will be completed in 1984.
Special issue on recent developments in plasma sources and new plasma regimes
Journal of Physics D: Applied Physics
To cite this article: Yuri Akishev et al 2019 J. Phys. D: Appl. Phys. 52 130301 View the article online for updates and enhancements. Recent citations Modification of the electric field distribution in a diffuse streamer-induced discharge under extreme overvoltage Alexandra Brisset et al -This content was downloaded from IP address 64.137.113.104 on 30/05
Electron holes, ion waves, and anomalous resistivity in space plasmas
Journal of Geophysical Research, 2006
1] Phase-space electron holes are seen in simulations, laboratory plasmas, and many regions of the Earth's space environment. We present simulations of beam plasmas showing that the generation and decay of electron holes results in a reduction of electron current, implying a parallel resistivity. We show that resistivity occurs in simulations where a cold electron beam is coincident with a warmer background plasma and appears to be mediated by the generation of ion acoustic waves propagating obliquely to the magnetic field. Initially, electron holes scatter electrons in the beam direction, steepening the electron beam distribution, eventually launching ion acoustic waves that cause resistivity and strong ion heating perpendicular toB. These effects occur in both strongly and weakly magnetized plasmas. Given that electron holes are observed in many space plasmas, these results have important implications for a number of magnetospheric and auroral ionospheric processes. For auroral plasmas, electron hole resistivity could support parallel electric fields on the order of several mV/m, accounting for parallel potential drops from tens to hundreds of eV. For the magnetopause, simulations show effective collision rates of 0.00015 w pe , which could enhance dissipation and diffusion across the boundary.