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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Variations In Solar Wind Fractionation As Seen By Ace/Swics And The Implications For Genesis Mission Results, P. Pilleri, Daniel B. Reisenfeld, T. H. Zurbuchen, S. T. Lepri, P. Shearer, J. A. Gilbert, R. Von Steiger, R. C. Wiens
Variations In Solar Wind Fractionation As Seen By Ace/Swics And The Implications For Genesis Mission Results, P. Pilleri, Daniel B. Reisenfeld, T. H. Zurbuchen, S. T. Lepri, P. Shearer, J. A. Gilbert, R. Von Steiger, R. C. Wiens
Physics and Astronomy Faculty Publications
We use Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer (SWICS) elemental composition data to compare the variations in solar wind (SW) fractionation as measured by SWICS during the last solar maximum (1999-2001), the solar minimum (2006-2009), and the period in which the Genesis spacecraft was collecting SW (late 2001-early 2004). We differentiate our analysis in terms in SW regimes (i.e., originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-first ionization potential (low-FIP) ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative …
Spectral Evolution Of Energetic Neutral Atom Emissions At The Heliospheric Poles As Measured By Ibex During Its First Three Yeras, M. Dayeh, F. Allegrini, R. Demajistre, M. I. Desai, R. W. Ebert, S. A. Fuselier, Paul H. Janzen, G. Livadiotis, D. J. Mccomas, Daniel B. Reisenfeld, N. A. Schwadron, M. Siewert
Spectral Evolution Of Energetic Neutral Atom Emissions At The Heliospheric Poles As Measured By Ibex During Its First Three Yeras, M. Dayeh, F. Allegrini, R. Demajistre, M. I. Desai, R. W. Ebert, S. A. Fuselier, Paul H. Janzen, G. Livadiotis, D. J. Mccomas, Daniel B. Reisenfeld, N. A. Schwadron, M. Siewert
Physics and Astronomy Faculty Publications
The Interstellar Boundary Explorer (IBEX) mission continues to measure energetic neutral atom (ENA) emissions produced by charge exchange between solar wind (SW) protons and interstellar neutrals at the edge of our heliosphere. Using the first 3 yr of IBEX-Hi ENA measurements (2009-2011), we examined the spectral evolution of ~0.5-6 keV ENAs at the polar regions (above 60°). We found the following: (1) pixels with a characteristic "ankle" spectra (lower spectral index at higher energies) increase by ~5% in 2010 and ~10% in 2011 compared to 2009. (2) The averaged spectral index in 2011 is smaller than that of 2009. (3) …
Ion Composition In Interchange Injection Events In Saturn's Magnetosphere, M. F. Thomsen, Daniel B. Reisenfeld, R. J. Wilson, M. Andriopoulou, F. J. Crary, G. B. Hospodarsky, C. M. Jackman, X. Jia, K. K. Khurana, C. Paranicas, E. Roussos, N. Sergis, R. L. Tokar
Ion Composition In Interchange Injection Events In Saturn's Magnetosphere, M. F. Thomsen, Daniel B. Reisenfeld, R. J. Wilson, M. Andriopoulou, F. J. Crary, G. B. Hospodarsky, C. M. Jackman, X. Jia, K. K. Khurana, C. Paranicas, E. Roussos, N. Sergis, R. L. Tokar
Physics and Astronomy Faculty Publications
Interchange injection events are commonly observed by the Cassini spacecraft in the region between about 6 and 12 Rs (1 Rs = 60,268 km) and even frequently beyond. In this study, 13 examples of interchange injection events are identified in Cassini-Cassini Plasma Spectrometer data under special conditions such that time-of-flight (TOF) mass spectra could be obtained from entirely within the events. Using the TOF data to separate the main ion species H+, H2+, and W+, approximate densities of each species are calculated under the assumption that all distributions were isotropic. The …
Separation Of The Ribbon From Globally Distributed Energetic Neutral Atom Flux Using The First Five Years Of Ibex Observations, N. A. Schwadron, E. Moebius, S. A. Fuselier, D. J. Mccomas, H. O. Funsten, Paul H. Janzen, Daniel B. Reisenfeld, H. Kucharek, M. A. Lee, K. Fairchild, F. Allegrini, M. Dayeh, G. Livadiotis, M. Reno, M. Bzowski, J. M. Sokol, M. A. Kubiak, E. R. Christian, R. Demajistre, P. Frisch, A. Galli, P. Wurz, M. Gruntman
Separation Of The Ribbon From Globally Distributed Energetic Neutral Atom Flux Using The First Five Years Of Ibex Observations, N. A. Schwadron, E. Moebius, S. A. Fuselier, D. J. Mccomas, H. O. Funsten, Paul H. Janzen, Daniel B. Reisenfeld, H. Kucharek, M. A. Lee, K. Fairchild, F. Allegrini, M. Dayeh, G. Livadiotis, M. Reno, M. Bzowski, J. M. Sokol, M. A. Kubiak, E. R. Christian, R. Demajistre, P. Frisch, A. Galli, P. Wurz, M. Gruntman
Physics and Astronomy Faculty Publications
The Interstellar Boundary Explorer (IBEX) observes the IBEX ribbon, which stretches across much of the sky observed in energetic neutral atoms (ENAs). The ribbon covers a narrow (∼20◦–50◦) region that is believed to be roughly perpendicular to the interstellar magnetic field. Superimposed on the IBEX ribbon is the globally distributed flux that is controlled by the processes and properties of the heliosheath. This is a second study that utilizes a previously developed technique to separate ENA emissions in the ribbon from the globally distributed flux. A transparency mask is applied over the ribbon and …
Ibex: The First Five Years (2009-2013), D. J. Mccomas, F. Allegrini, M. Bzowski, M. A. Dayeh, R. Demajistre, H. O. Funsten, S. A. Fuselier, M. Gruntman, Paul H. Janzen, M. A. Kubiak, H. Kucharek, E. Möbius, Daniel B. Reisenfeld, N. A. Schwadron, J. M. Sokol, M. Tokumaru
Ibex: The First Five Years (2009-2013), D. J. Mccomas, F. Allegrini, M. Bzowski, M. A. Dayeh, R. Demajistre, H. O. Funsten, S. A. Fuselier, M. Gruntman, Paul H. Janzen, M. A. Kubiak, H. Kucharek, E. Möbius, Daniel B. Reisenfeld, N. A. Schwadron, J. M. Sokol, M. Tokumaru
Physics and Astronomy Faculty Publications
The Interstellar Boundary Explorer (IBEX) returned its first five years of scientific observations from 2009 to 2013. In this study, we examine, validate, initially analyze, and provide to the broad scientific community this complete set of energetic neutral atom (ENA) observations for the first time. IBEX measures the fluxes of ENAs reaching 1 AU from sources in the outer heliosphere and most likely the very nearby interstellar space beyond the heliopause. The data, maps, and documentation provided in this study represent the fourth major release of the IBEX data, incorporate important improvements, and should be used for future studies and …
Properties Of High-Latitude Cme-Driven Disturbances During Ulysses Second Northern Polar Passage, Daniel B. Reisenfeld, J. T. Gosling, R. J. Forsyth, P. Riley, O. C. St. Cyr
Properties Of High-Latitude Cme-Driven Disturbances During Ulysses Second Northern Polar Passage, Daniel B. Reisenfeld, J. T. Gosling, R. J. Forsyth, P. Riley, O. C. St. Cyr
Physics and Astronomy Faculty Publications
Ulysses observed five coronal mass ejections (CMEs) and their associated disturbances while the spacecraft was immersed in the polar coronal hole (CH) flow above 70° N in late 2001. Of these CMEs, two were very fast (>850 km s−1) driving strong shocks in the wind ahead, and two others were over-expanding. The two fast CMEs were observed leaving the Sun by LASCO/SOHO, and were observed in the ecliptic by Genesis and ACE. These were large events, spanning at least from the northern heliospheric pole to the ecliptic. One-dimensional hydrodynamic simulations indicate that these could be described as …
Evidence Of A Solar Origin For Pressure Balance Structures In The High-Latitude Solar Wind, Daniel B. Reisenfeld, D. J. Mccomas, J. T. Steinberg
Evidence Of A Solar Origin For Pressure Balance Structures In The High-Latitude Solar Wind, Daniel B. Reisenfeld, D. J. Mccomas, J. T. Steinberg
Physics and Astronomy Faculty Publications
Ulysses observations of the high-latitude solar wind have shown that on time scales of < 1 day, the polar wind is dominated by pressure balance structures (PBSs). Fluctuations of the plasma beta within PBSs appear to be strongly correlated with fluctuations in the helium abundance. The correlation occurs in both the northern and southern hemispheres. In addition, a mechanism is apparently at work in the high-latitude solar wind that dissipates the beta/He correlation over a distance of a few AU. Solar wind composition is established at the base of the corona; thus, the He abundance signature strongly suggests the observed solar wind PBSs are associated with structures low in the solar atmosphere. In particular, high-beta structures appear to originate in locations of enhanced He abundance. We suggest an interpretation of the high-beta portion of PBSs as the solar wind extensions of polar plumes.