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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Progress of the laser ion source upgrade (LION2) for RHIC and NSRL program at Brookhaven National Laboratory

At Brookhaven National Laboratory (BNL), the LION2 ion source is being constructed to replace an existing laser ion ablation ion source (LIS) at the EBIS facility, which provides heavy ion beams of multiple ion species for the operation of NASA Space Radiation Laboratory (NSRL) and Relativistic Heavy Ion Collider (RHIC). The LION1 ion source currently provides singly charged ions of Li, B, C, O, Al, Si, Ca, Ti, Fe, Cu, Zr, Nb, Ag, Tb, Ta, W, Au, Bi, and Th with a rapid-species-change capability. An electron beam ion source, Extended-EBIS captures, confines, and ionizes the ions to high charge state, suitable for injection and acceleration by an RFQ accelerator. Typically, single pulses of the LIS ion species for NSRL are changed sequentially during Galactic Cosmic Ray experiments, while multiple pulses of a given ion beam are provided quasi-simultaneously for RHIC. LION2 will have the same capability of the rapid-species-change with improved beam performance and reliability. LION2 is being constructed in a remote assembly location and is expected to finish in December 2023. The removal of LION1 and installation of LION2 is planned during the December 2023 or summer 2024 shutdown.

43 PARTICLE ACCELERATORS↗
NASA NTRS1990

Ion composition in and near the frontside boundary layer

A unique set of magnetopause crossings by the AMPTE/CCE spacecraft from near its 8.8 R(E) apogee is used to identify 13 crossings within the first two years after launch time that contain significant data intervals in the magnetosheath, boundary layer, and nearby outer magnetosphere. It is concluded that shocked solar wind or magnetosheath ions as well as ions from the outer magnetosphere overlap the boundary layer. Low-energy He(2+) as well as high charge state CNO, Si, and Fe group ions clearly overlap the boundary layer from their solar wind source. Similarly, O(+), N(+), O2(+) and NO(+) + O2(+) overlap the boundary layer from their magnetospheric source region. It is found that ion densities in the boundary layer are roughly one half those observed in the respective source regions, and that ion transport across the boundary layer is a one-way process with dawn-dusk asymmetry.

Eastman, T. E.↗
NASA NTRS1973

Daytime ion chemistry of N2+.

Rocket measurements of the emission of the (0, 0) first negative band of N2+ at 3914 A in the day airglow have been made between 120 and 300 km. The solar zenith angle at the time of the flight was 60 deg, and the zenith intensity above 120 km was 1.6 kR averaged over both legs of the flight. The data are compared with a model in which charge exchange of N2 with metastable O+(2D) ions is included as an additional source of N2 ionization. Above 240 km this mechanism is dominant over the photoionization of N2 by solar extreme ultraviolet radiation. The derived N2+ density is consistent with the results of rocket-borne mass spectrometric observations.

Feldman, P. D.↗
NASA NTRS1973

Study of neutral composition of lower thermosphere at Fort Churchill.

On Feb. 4 and 6, 1969, and May 11, 1970, Aerobee rockets carrying neutral mass spectrometers were flown at Fort Churchill, Canada during conditions of low geomagnetic activity. As in earlier flights at White Sands, New Mexico, each rocket carried both 'open' and 'closed' ion source instruments. Vertical profiles of N2, O2, O, Ar, and He were measured. Results obtained were essentially the same as those observed at White Sands except that for the winter flights helium appeared to be in diffusive equilibrium.

Nier, A. O.↗
NASA NTRS1990

Collisional electrostatic ion cyclotron waves as a possible source of energetic heavy ions in the magnetosphere

A new mechanism is proposed for the source of energetic heavy ions (NO/+/, O2/+/, and O/+/) found in the magnetosphere. Simulations using a multispecies particle simulation code for resistive current-driven electrostatic ion cyclotron waves show transverse and parallel bulk heating of bottomside ionospheric heavy ion populations. The dominant mechanism for the transverse bulk heating is resonant ion heating by wave-particle ion trapping. Using a linear kinetic dispersion relation for a magnetized, collisional, homogenous, and multiion plasma, it is found that collisional electrostatic ion cyclotron waves near the NO(+), O2(+), and O(+) gyrofrequencies are unstable to field-aligned currents of 50 microA/sq m for a typical bottomside ionosphere.

Providakes, Jason↗
NASA NTRS1993

Thermal structure of ions and electrons in Saturn's inner magnetosphere

A theoretical model of thermal ion and electron temperatures in Saturn's inner magnetospheres is presented which is based on a fast model of radial diffusive plasma transport. It is shown that the ion and electron temperatures and the latitudinal behavior of temperatures are consistent with the fast diffusion hypothesis, assuming that O(+) is the dominant ion and that its source is the Dione-Tethys plasma torus. The present results reinforce the conclusions of Barbosa (1990).

Barbosa, D. D.↗
NASA NTRS2005

Laboratory Studies in UV and EUV Solar Physics

A new 5 GHZ Electron Cyclotron Resonance (ECR) ion source for SAO's Ion Beam Experiment was designed, built and tested. Absolute cross sections were measured for electron impact excitation (EIE) in C(2+) (2s2p (3)P(sup o) - 2p(sup 2) (3)P), and empirical EIE rate coefficients were derived. The absolute cross section for EIE in Si(2+) (3s3p (3)P(sup o) - 3s3p (1)P(sup o)) was measured, and our experimental values for absolute cross sections for EIE in C(3+) (2s (2)S - 2p (2)P(sup o)) were reanalyzed and compared to values obtained by other experimental methods and by theory. In addition, a paper was published. The development and testing of the new ion source, the Si(2+) EIE measurements, and the reevaluation of the cross sections for C(3+) resulted from the Ph.D. research of Paul H. Janzen who completed the degree requirements for the Harvard University Department of Physics in 2002. John Kohl served as the Ph.D.Thesis Advisor. Because of delays in bringing the new ion source on line, the measurements of EIE in C(2+) (2s2p (3)P(sup o) - (2)p(sup 2) (3)P) were not completed until 2004. Preparations for measurements of EIE in C(2+) (1s(sup 2) (1)S - 2s2p (1)P(sup o)) are currently underway.

Wagner, William J.↗
NASA NTRS2008

Energy and Mass Transport of Magnetospheric Plasmas during the November 2003 Magnetic Storm

Intensive energy and mass transport from the solar wind across the magnetosphere boundary is a trigger of magnetic storms. The storm on 20-21 November 2003 was elicited by a high-speed solar wind and strong southward component of interplanetary magnetic field. This storm attained a minimum Dst of -422 nT. During the storm, some of the solar wind particles enter the magnetosphere and eventually become part of the ring current. At the same time, the fierce solar wind powers strong outflow of H+ and O+ from the ionosphere, as well as from the plasmasphere. We examine the contribution of plasmas from the solar wind, ionosphere and plasmasphere to the storm-time ring current. Our simulation shows, for this particular storm, ionospheric O+ and solar wind ions are the major sources of the ring current particles. The polar wind and plasmaspheric H+ have only minor impacts. In the storm main phase, the strong penetration of solar wind electric field pushes ions from the geosynchronous orbit to L shells of 2 and below. Ring current is greatly intensified during the earthward transport and produces a large magnetic depression in the surface field. When the convection subsides, the deep penetrating ions experience strong charge exchange loss, causing rapid decay of the ring current and fast initial storm recovery. Our simulation reproduces very well the storm development indicated by the Dst index.

Fok, Mei-Chging↗
NASA NTRS1975

On the origin of 4640-4650 A emission in X-ray stars

The origin is investigated for a prominent and rapidly variable emission feature near the 4640-A line which has been observed in the optical counterparts of Sco X-1, Cyg X-2, Her X-1, Cen X-3, 3U 0900-40, and 3U 1700-37. It is suggested that the emission is generated in the vicinity of a compact X-ray source by the interaction of X-rays with nearby gaseous matter and that three likely sources of the emission are the ions C III, N III, and O II. Results are presented for a detailed mathematical model of an X-ray source surrounded by a uniform distribution of matter and are used to evaluate possible emission mechanisms. It is concluded that selective emission of N III (4634 to 4641 A) in the Bowen fluorescence process may be the responsible mechanism.

Mcclintock, J. E.↗
NASA NTRS1970

An investigation of the ionospheric D region at sunrise

The growth over sunrise of the C and D layers of the ionosphere is investigated. The model which is analyzed includes the negative ion species O(-), O2(-), O3(-), O4(-), NO3(-), CO3(-), and CO4(-). Ionization sources due to galactic cosmic rays, precipitated electrons, ionization of NO by scattered Lyman alpha radiation, and the direct solar radiation ionization are also included. The photodetachment of most of the negative ions is discussed, as well as the time variation of these parameters. The time variations of the electron, negative ion, and positive ion densities are calculated over sunrise. From these data, the mesospheric C and D layer development is plotted. Several model parameters are varied until the best agreement with experimentally determined electron densities is obtained. The results are discussed in light of several atmospheric parameters including the O and NO concentrations and the electron-ion recombination coefficient.

Turco, R. P.↗
NASA NTRS1992

Transverse ion acceleration by localized lower hybrid waves in the topside auroral ionosphere

Up to now, observations had been unable to show conclusively a one-to-one correspondence between perpendicular ion acceleration and a particular type of plasma wave within the O(+) source region below 2000 km. In this paper we demonstrate that intense (100-300 mV/m) lower hybrid waves are responsible for transversely accelerating H(+) and O(+) ions to characteristic energies of up to 6 eV. This wave-particle interaction takes place in thin filamentary density cavities oriented along geomagnetic field lines. The measurements we discuss were conducted in the nightside auroral zone at latitudes between 500 km and 1100 km. Our results are consistent with theories of lower hybrid wave condensation and collapse.

Vago, J. L.↗
NASA NTRS1994

Formation of Na-containing molecular ions at Io

Fast sodium atoms, which appear to be associated with the motion of the magnetic 'field lines' downstream from Io (Schneider et al. 1991), are thought to be produced by dissociation of NaX(+) in Io's plasma torus. It was suggested that these molecular ions are formed near Io's exobase by electron-impact ionization and picked up be the corotating filed lines (Wilson and Schneider 1994). Because electron cooling processes dominate electron-impact ionization in Io's corona, two reactions are suggested here as sources of NaX(+) and, hence, as the ultimate sources of the observed fast Na. First, the charge-exchange cross sections for forming NaX(+) are shown to be large for plasma torus ions (O(+), S(+), O(2+), S(3+)) colliding with NaX molecules in Io's corona. Sputtering from the surface (Chrisey et al. 1988) and rapid transport to the exobase is a potential source of NaX, where X is O,S, Na, or a molecular species such as NaS or O2. Second ions of the more abundant molecules (e.g., SO(+), SO2(+), O2(+), and S2(+)) can react efficiently with atomic Na in Io's corona to form NaX(+). Here cross sections are estimated for these two processes, as well as for charge exchange in O(+) and S(+) on Na collisions.

Johnson, R. E.↗
NASA NTRS1994

Atomic data from the iron project. 3: Rate coefficients for electron impact excitation of boron-like ions: Ne VI, Mg VIII, Al IX, Si X, S XII, Ar XIV, Ca XVI and Fe XXII

Collison strengths and maxwellian averaged rate coefficients have been calculated for the 105 transitions among all 15 fine structure levels of the 8 LS terms 2s(sup 2) 2 P(P-2(sup 0 sub 1/, 3/2)), 2s2p(sup 2)(P-4(sub 1/2,3/2,5/2), D-2(sub 3/2, 5/2), S-2(sub 1/2), P-2(sub 1/2, 3/2)), 2p(sup 3)(S-4(sup 0)(sub 3/2), D-2(sup 0 sub 3/2, 5/2), P-2(sup 0 sub 1/2, 3/2)) in highly- charged B-like Ne, Mg, Al, Si, S, Ar, Ca and Fe. Rate coefficients have been tabulated at a wide range of temperatures, depending on the ion charge and abundance in plasma sources. Earlier work for O IV has also been extended to include the high temperature range. A brief discussion of the calculations, sample results, and comparison with earlier works is also given. While much of the new data should be applicable to UV spectral diagnostics, the new rates for the important ground state fine structure transition P-2(sup 0 sub 1/2)-P-2(sup 0 sub 3/2) should result in significant revision of the IR cooling rates in plasmas where B-like ions are prominent constituents, since the new rate coefficients are generally higher by several factors compared with the older data.

Zhang, Hong Lin↗
NASA NTRS1982

The ionosphere as a source for magnetospheric ions

Ion composition measurements within the past several years have shown O(+), He(+), and other ions of terrestrial origin to compose a substantial fraction of the magnetospheric ion population. This review examines (1) observations of topside ionospheric composition, (2) mechanisms for energization and injection of ionospheric ions into the magnetosphere, and (3) observations of ions of ionospheric origin in various regions of the magnetosphere, including the plasmasphere, ring current, magnetotail plasma sheet and lobes, and boundary layer and magnetosheath.

Horwitz, J. L.↗
NASA NTRS1987

Solar cycle changes in the ionization sources of the nightside Venus ionosphere

Using new and previous experimental evidence, it is argued that the height-integrated flux of O(+) ions transported from the dayside Venus ionosphere into the nightside ionosphere is strongly reduced (shut off) at solar cycle minimum (SCmin) and that the electron impact source becomes the predominant nightside ionization source during this phase of the solar cycle. The height-integrated transterminator O(+) flux, which is probably the dominant nightside ionization source at solar cycle maximum (SCmax), is shut off at SCmin by compression of the dayside ionopause to low altitude. It is suggested that the ionopause is depressed because the dayside ionospheric kinetic pressure field is reduced by a factor of approximately 3 from its SCmas value and that the typical SCmin solar wind dynamic pressure, which is not less than the typical SCmax value, cannot be balanced by the ionospheric pressure field at altitudes above approximately 250 km.

Knudsen, William C.↗
NASA NTRS1991

Superthermal over 36-eV ions observed in the near-tail region of Venus by the Pioneer Venus Orbiter neutral mass spectrometer

The PVO neutral mass spectrometer has measured the over 36-eV ions in the 1300-3700 km altitude range for solar zenith angles greater than 120 deg. The composition is mainly O(+), but He(+), N(+), NO(+), and O2(+) have been identified. The average O(+) flux is about 100,000/sq cm/s, but higher fluxes from 10 to the 6th to 10 to the 8th/sq cm/s are observed about 10 percent of the time. The directions of the apparent O(+) flow in the ecliptic plane show predominantly tailward components with a smaller number of nontailward components. The over 36-eV O(+) escape flux in the ionotail is estimated to be about 100,000/sq cm/s. The O(+) flux data show a factor of 2.5 increase from solar minimum to maximum, implying a photoionization source for these ions. The composition of the superthermal ions in the ionotail suggests that their source is most likely the high-altitude nightside ionosphere. Transport of superthermal O(+) across the terminator to the nightside has been observed.

Kasprzak, W. T.↗
NASA NTRS1979

Energetic oxygen - A direct coupling mechanism between the magnetosphere and thermosphere

The study investigates the effects of the precipitation of energetic O(+) ions (0.7 - 12 keV) into the atmosphere during magnetic storms. The energetic O(+) ion flux produces a splash of lower energy neutral oxygen atoms at the top of the atmosphere. As a result of the photo-ionization and charge exchange with H(+) ions in the plasmasphere, these backscattered atoms produce a low energy O(+) flux that is more than 10 times larger in magnitude than the original energetic O(+) flux. The energetic O(+) events thus provide a potential source mechanism for the lower energy (no greater than about 30 eV) O(+) ions observed in the plasmasphere. It is also suggested that the energetic ion events may be self-sustaining in that some of the ionized 'splash' particles (no greater than about 10%) are subsequently accelerated by an as yet unidentified mechanism to the higher observed energies. It is found that 96% of the incoming energy is transferred to the neutral atmosphere in the form of heating. Measured fluxes indicate heating rates as high as about 0.4 erg/sq cm/sec/ster.

Torr, M. R.↗