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145 results on '"Plunkett, S. P."'

1. The Solar Orbiter Science Activity Plan: translating solar and heliospheric physics questions into action

Author

Zouganelis, I., De Groof, A., Walsh, A. P., Williams, D. R., Mueller, D., Cyr, O. C. St, Auchere, F., Berghmans, D., Fludra, A., Horbury, T. S., Howard, R. A., Krucker, S., Maksimovic, M., Owen, C. J., Rodriiguez-Pacheco, J., Romoli, M., Solanki, S. K., Watson, C., Sanchez, L., Lefort, J., Osuna, P., Gilbert, H. R., Nieves-Chinchilla, T., Abbo, L., Alexandrova, O., Anastasiadis, A., Andretta, V., Antonucci, E., Appourchaux, T., Aran, A., Arge, C. N., Aulanier, G., Baker, D., Bale, S. D., Battaglia, M., Rubio, L. Bellot, Bemporad, A., Berthomier, M., Bocchialini, K., Bonnin, X., Brun, A. S., Bruno, R., Buchlin, E., Buechner, J., Bucik, R., Carcaboso, F., Carr, R., Carrasco-Blazquez, I., Cecconi, B., Cangas, I. Cernuda, Chen, C. H. K., Chitta, L. P., Chust, T., Dalmasse, K., D'Amicis, R., Da Deppo, V., De Marco, R., Dolei, S., Dolla, L., de Wit, T. Dudok, van Driel-Gesztelyi, L., Eastwood, J. P., Lara, F. Espinosa, Etesi, L., Fedorov, A., Felix-Redondo, F., Fineschi, S., Fleck, B., Fontaine, D., Fox, N. J., Gandorfer, A., Genot, V., Georgoulis, M. K., Gissot, S., Giunta, A., Gizon, L., Gomez-Herrero, R., Gontikakis, C., Graham, G., Green, L., Grundy, T., Haberreiter, M., Harra, L. K., Hassler, D. M., Hirzberger, J., Ho, G. C., Hurford, G., Innes, D., Issautier, K., James, A. W., Janitzek, N., Janvier, M., Jeffrey, N., Jenkins, J., Khotyaintsev, Y., Klein, K. -L., Kontar, E. P., Kontogiannis, I., Krafft, C., Krasnoselskikh, V., Kretzschmar, M., Labrosse, N., Lagg, A., Landini, F., Lavraud, B., Leon, I., Lepri, S. T., Lewis, G. R., Liewer, P., Linker, J., Livi, S., Long, D. M., Louarn, P., Malandraki, O., Maloney, S., Martinez-Pillet, V., Martinovic, M., Masson, A., Matthews, S., Matteini, L., Meyer-Vernet, N., Moraitis, K., Morton, R. J., Musset, S., Nicolaou, G., Nindos, A., O'Brien, H., Suarez, D. Orozco, Owens, M., Pancrazzi, M., Papaioannou, A., Parenti, S., Pariat, E., Patsourakos, S., Perrone, D., Peter, H., Pinto, R. F., Plainaki, C., Plettemeier, D., Plunkett, S. P., Raines, J. M., Raouafi, N., Reid, H., Retino, A., Rezeau, L., Rochus, P., Rodriguez, L., Rodriguez-Garcia, L., Roth, M., Rouillard, A. P., Sahraoui, F., Sasso, C., Schou, J., Schuehle, U., Sorriso-Valvo, L., Soucek, J., Spadaro, D., Stangalini, M., Stansby, D., Steller, M., Strugarek, A., Stverak, S., Susino, R., Telloni, D., Terasa, C., Teriaca, L., Toledo-Redondo, S., Iniesta, J. C. del Toro, Tsiropoula, G., Tsounis, A., Tziotziou, K., Valentini, F., Vaivads, A., Vecchio, A., Velli, M., Verbeeck, C., Verdini, A., Verscharen, D., Vilmer, N., Vourlidas, A., Wicks, R., Wimmer-Schweingruber, R. F., Wiegelmann, T., Young, P. R., and Zhukov, A. N.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Solar Orbiter is the first space mission observing the solar plasma both in situ and remotely, from a close distance, in and out of the ecliptic. The ultimate goal is to understand how the Sun produces and controls the heliosphere, filling the Solar System and driving the planetary environments. With six remote-sensing and four in-situ instrument suites, the coordination and planning of the operations are essential to address the following four top-level science questions: (1) What drives the solar wind and where does the coronal magnetic field originate? (2) How do solar transients drive heliospheric variability? (3) How do solar eruptions produce energetic particle radiation that fills the heliosphere? (4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? Maximising the mission's science return requires considering the characteristics of each orbit, including the relative position of the spacecraft to Earth (affecting downlink rates), trajectory events (such as gravitational assist manoeuvres), and the phase of the solar activity cycle. Furthermore, since each orbit's science telemetry will be downloaded over the course of the following orbit, science operations must be planned at mission level, rather than at the level of individual orbits. It is important to explore the way in which those science questions are translated into an actual plan of observations that fits into the mission, thus ensuring that no opportunities are missed. First, the overarching goals are broken down into specific, answerable questions along with the required observations and the so-called Science Activity Plan (SAP) is developed to achieve this. The SAP groups objectives that require similar observations into Solar Orbiter Observing Plans (SOOPs), resulting in a strategic, top-level view of the optimal opportunities for science observations during the mission lifetime., Comment: 20 pages, 1 figure, accepted by Astronomy & Astrophysics

Published
2020
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2. New constraints on oscillation parameters from $\nu_e$ appearance and $\nu_\mu$ disappearance in the NOvA experiment

Author

Acero, M. A., Adamson, P., Alion, L. Aliaga T., Allakhverdian, V., Antoshkin, N. Anfimov A., Arrieta-Diaz, E., Back, A. Aurisano A., Backhouse, C., Balashov, M. Baird N., Bambah, B. A., Behera, K. Bays B., Bending, S., Bhatnagar, R. Bernstein V., Bhuyan, B., Blackburn, J. Bian T., Blair, J., Bour, A. Bolshakova P., Bromberg, C., Buchanan, J. Brown N., Butkevich, A., Campbell, V. Bychkov M., Carroll, T. J., Cedeno, E. Catano-Mur A., Childress, S., Chowdhury, B. C. Choudhary B., Coan, T. E., Cooper, M. Colo J., Corwin, L., Cronin-Hennessy, L. Cremonesi D., Davies, G. S., De Rijck, J. P. Davies S., Derwent, P. F., Ding, R. Dharmapalan P., Djurcic, Z., Dung, E. C. Dukes P., Duyang, H., Ehrlich, S. Edayath R., Feldman, G. J., Gallagher, M. J. Frank H. R., Gandrajula, R., Germani, F. Gao S., Giri, A., Goodman, R. A. Gomes M. C., Grichine, V., Group, M. Groh R., Grover, D., Habig, B. Guo A., Hakl, F., Hatcher, J. Hartnell R., Hatzikoutelis, A., Himmel, K. Heller A., Holin, A., Huang, B. Howard J., Hylen, J., Judah, F. Jediny M., Kakorin, I., Kaplan, D. Kalra D. M., Keloth, R., Koerner, O. Klimov L. W., Kolupaeva, L., Kourbanis, S. Kotelnikov I., Kreymer, A., Kumar, Ch. Kulenberg A., Kuruppu, C., Lackey, V. Kus T., Lang, K., Lokajicek, S. Lin M., Lozier, J., Maan, S. Luchuk K., Magill, S., Marshak, W. A. Mann M. L., Matveev, V., Messier, D. P. Méndez M. D., Meyer, H., Miller, T. Miao W. H., Mishra, S. R., Mohanta, A. Mislivec R., Moren, A., Muether, L. Mualem M., Mufson, S., Musser, R. Murphy J., Naples, D., Nelson, N. Nayak J. K., Nichol, R., Norman, E. Niner A., Nosek, T., Olshevskiy, Y. Oksuzian A., Olson, T., Patterson, J. Paley R. B., Pawloski, G., Petrova, D. Pershey O., Petti, R., Plunkett, S. Phan-Budd R. K., Potukuchi, B., Psihas, C. Principato F., Radovic, A., Rebel, R. A. Rameika B., Rojas, P., Sachdev, V. Ryabov K., Samoylov, O., Sepulveda-Quiroz, M. C. Sanchez J., Shanahan, P., Singh, A. Sheshukov P., Singh, V., Smolik, E. Smith J., Snopok, P., Song, N. Solomey E., Sousa, A., Strait, K. Soustruznik M., Suter, L., Tas, R. L. Talaga P., Thayyullathil, R. B., Tiras, J. Thomas E., Tognini, S. C., Tripathi, D. Torbunov J., Tsaris, A., Urheim, Y. Torun J., Vahle, P., Vinton, J. Vasel L., Vokac, P., Vrba, A. Vold T., Wang, B., Wetstein, T. K. Warburton M., Whittington, D., Wolcott, S. G. Wojcicki J., Yang, S., Zalesak, S. Yu J., Zamorano, B., and Zwaska, R.

Subjects
High Energy Physics - Experiment
Abstract

We present updated results from the NOvA experiment for $\nu_\mu\rightarrow\nu_\mu$ and $\nu_\mu\rightarrow\nu_e$ oscillations from an exposure of $8.85\times10^{20}$ protons on target, which represents an increase of 46% compared to our previous publication. The results utilize significant improvements in both the simulations and analysis of the data. A joint fit to the data for $\nu_\mu$ disappearance and $\nu_e$ appearance gives the best fit point as normal mass hierarchy, $\Delta m^2_{32} = 2.44\times 10^{-3}{{\rm eV}^2}/c^4$, $\sin^2\theta_{23} = 0.56$, and $\delta_{CP} = 1.21\pi$. The 68.3% confidence intervals in the normal mass hierarchy are $\Delta m^2_{32} \in [2.37,2.52]\times 10^{-3}{{\rm eV}^2}/c^4$, $\sin^2\theta_{23} \in [0.43,0.51] \cup [0.52,0.60]$, and $\delta_{CP} \in [0,0.12\pi] \cup [0.91\pi,2\pi]$. The inverted mass hierarchy is disfavored at the 95% confidence level for all choices of the other oscillation parameters.

Published
2018
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3. Near-Sun observations of an F-corona decrease and K-corona fine structure

Author

Howard, R. A., Vourlidas, A., Bothmer, V., Colaninno, R. C., DeForest, C. E., Gallagher, B., Hall, J. R., Hess, P., Higginson, A. K., Korendyke, C. M., Kouloumvakos, A., Lamy, P. L., Liewer, P. C., Linker, J., Linton, M., Penteado, P., Plunkett, S. P., Poirier, N., Raouafi, N. E., Rich, N., Rochus, P., Rouillard, A. P., Socker, D. G., Stenborg, G., Thernisien, A. F., and Viall, N. M.

Published
2019
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4. Stereoscopic Polar Plume Reconstructions from Stereo/Secchi Images

Author

Feng, L., Inhester, B., Solanki, S. K., Wilhelm, K., Wiegelmann, T., Podlipnik, B., Howard, R. A., Plunkett, S. P., Wuelser, J. P., and Gan, W. Q.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We present stereoscopic reconstructions of the location and inclination of polar plumes of two data sets based on the two simultaneously recorded images taken by the EUVI telescopes in the SECCHI instrument package onboard the \emph{STEREO (Solar TErrestrial RElations Observatory)} spacecraft. The ten plumes investigated show a superradial expansion in the coronal hole in 3D which is consistent with the 2D results. Their deviations from the local meridian planes are rather small with an average of $6.47^{\circ}$. By comparing the reconstructed plumes with a dipole field with its axis along the solar rotation axis, it is found that plumes are inclined more horizontally than the dipole field. The lower the latitude is, the larger is the deviation from the dipole field. The relationship between plumes and bright points has been investigated and they are not always associated. For the first data set, based on the 3D height of plumes and the electron density derived from SUMER/\emph{SOHO} Si {\sc viii} line pair, we found that electron densities along the plumes decrease with height above the solar surface. The temperature obtained from the density scale height is 1.6 to 1.8 times larger than the temperature obtained from Mg {\sc ix} line ratios. We attribute this discrepancy to a deviation of the electron and the ion temperatures. Finally, we have found that the outflow speeds studied in the O {\sc vi} line in the plumes corrected by the angle between the line of sight and the plume orientation are quite small with a maximum of 10 $\mathrm{km s^{-1}}$. It is unlikely that plumes are a dominant contributor to the fast solar wind., Comment: 25 pages, 13 figures

Published
2009
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5. 3D Coronal Slow Modes: Towards 3D Seismology

Author

Marsh, M. S., Walsh, R. W., and Plunkett, S.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

On 2008 January 10, the twin Solar Terrestrial Relations Observatory (STEREO) A and B spacecraft conducted a high time cadence study of the solar corona with the Extreme UltraViolet Imager (EUVI) instruments with the aim of investigating coronal dynamics. Observations of the three-dimensional propagation of waves within active region coronal loops and a measurement of the true coronal slow mode speed are obtained. Intensity oscillations with a period of approximately 12 minutes are observed to propagate outwards from the base of a loop system, consistent with the slow magnetoacoustic mode. A novel analysis technique is applied to measure the wave phase velocity in the observations of the A and B spacecraft. These stereoscopic observations are used to infer the three-dimensional velocity vector of the wave propagation, with an inclination of 37 +- 6 deg to the local normal and a magnitude of 132 +- 9 and 132 +- 11 km s-1, giving the first measurement of the true coronal longitudinal slow mode speed, and an inferred temperature of 0.84 +- 12 MK and 0.84 +- 15 MK., Comment: In press, ApJ June 2009 - 1 v697 issue

Published
2009
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6. Comprehensive Observations of a Solar Minimum CME with STEREO

Author

Wood, B. E., Howard, R. A., Plunkett, S. P., and Socker, D. G.

Subjects
Astrophysics
Abstract

We perform the first kinematic analysis of a CME observed by both imaging and in situ instruments on board STEREO, namely the SECCHI, PLASTIC, and IMPACT experiments. Launched on 2008 February 4, the CME is tracked continuously from initiation to 1 AU using the SECCHI imagers on both STEREO spacecraft, and is then detected by the PLASTIC and IMPACT particle and field detectors on board STEREO-B. The CME is also detected in situ by ACE and SOHO/CELIAS at Earth's L1 Lagrangian point. The CME hits STEREO-B, ACE, and SOHO on 2008 February 7, but misses STEREO-A entirely. This event provides a good example of just how different the same event can look when viewed from different perspectives. We also demonstrate many ways in which the comprehensive and continuous coverage of this CME by STEREO improves confidence in our assessment of its kinematic behavior, with potential ramifications for space weather forecasting. The observations provide several lines of evidence in favor of the observable part of the CME being narrow in angular extent, a determination crucial for deciding how best to convert observed CME elongation angles from Sun-center to actual Sun-center distances., Comment: 27 pages, 10 figures, AASTEX v5.2, accepted by ApJ

Published
2008
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7. A Search for Ultra-High Energy Counterparts to Gamma-Ray Bursts

Author

Plunkett, S. P., Delaney, M., McBreen, B., Hurley, K. J., and O'Sullivan, C. T.

Subjects
Astrophysics
Abstract

A small air shower array operating over many years has been used to search for ultra-high energy (UHE) gamma radiation ($\geq 50$ TeV) associated with gamma-ray bursts (GRBs) detected by the BATSE instrument on the Compton Gamma-Ray Observatory (CGRO). Upper limits for a one minute interval after each burst are presented for seven GRBs located with zenith angles $\theta < 20^{\circ}$. A $4.3\sigma$ excess over background was observed between 10 and 20 minutes following the onset of a GRB on 11 May 1991. The confidence level that this is due to a real effect and not a background fluctuation is 99.8\%. If this effect is real then cosmological models are excluded for this burst because of absorption of UHE gamma rays by the intergalactic radiation fields., Comment: 4 pages LaTeX with one postscript figure. This version does not use kluwer.sty and will allow automatic postscript generation

Published
1995
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8. Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI)

Author

Howard, R. A., Moses, J. D., Vourlidas, A., Newmark, J. S., Socker, D. G., Plunkett, S. P., Korendyke, C. M., Cook, J. W., Hurley, A., Davila, J. M., Thompson, W. T., St Cyr, O. C., Mentzell, E., Mehalick, K., Lemen, J. R., Wuelser, J. P., Duncan, D. W., Tarbell, T. D., Wolfson, C. J., Moore, A., Harrison, R. A., Waltham, N. R., Lang, J., Davis, C. J., Eyles, C. J., Mapson-Menard, H., Simnett, G. M., Halain, J. P., Defise, J. M., Mazy, E., Rochus, P., Mercier, R., Ravet, M. F., Delmotte, F., Auchere, F., Delaboudiniere, J. P., Bothmer, V., Deutsch, W., Wang, D., Rich, N., Cooper, S., Stephens, V., Maahs, G., Baugh, R., McMullin, D., Carter, T., and Russell, C. T., editor

Published
2008
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9. The Relationship of Green-Line Transients to White-Light Coronal Mass Ejections

Author

Plunkett, S. P., Brueckner, G. E., Dere, K. P., Howard, R. A., Koomen, M. J., Korendyke, C. M., Michels, D. J., Moses, J. D., Moulton, N. E., Paswaters, S. E., Cyr, O. C. St., Socker, D. G., Wang, D., Simnett, G. M., Bedford, D. K., Biesecker, D. A., Eyles, C. J., Tappin, S. J., Schwenn, R., Lamy, P. L., Llebaria, A., Fleck, B., editor, and Švestka, Z., editor

Published
1997
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11. First View of the Extended Green-Line Emission Corona at Solar Activity Minimum Using the LASCO-C1 Coronagraph on SOHO

Author

Schwenn, R., Inhester, B., Plunkett, S. P., Epple, A., Podlipnik, B., Bedford, D. K., Eyles, C. J., Simnett, G. M., Tappin, S. J., Bout, M. V., Lamy, P. L., Llebaria, A., Brueckner, G. E., Dere, K. P., Howard, R. A., Koomen, M. J., Korendyke, C. M., Michels, D. J., Moses, J. D., Moulton, N. E., Paswaters, S. E., Socker, D. G., Cyr, O. C. St., Wang, D., Fleck, B., editor, and Švestka, Z., editor

Published
1997
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16. Calibration of the Soho/Lasco C3 White Light Coronagraph

Author

Morrill, J. S., Korendyke, C. M., Brueckner, G. E., Giovane, F., Howard, R. A., Koomen, M., Moses, D., Plunkett, S. P., Vourlidas, A., Esfandiari, E., Rich, N., Wang, D., Thernisien, A. F., Lamy, P., Llebaria, A., Biesecker, D., Michels, D., Gong, Q., and Andrews, M.

Published
2006
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18. The Solar Orbiter Science Activity Plan

Author

Zouganelis, I., primary, De Groof, A., additional, Walsh, A. P., additional, Williams, D. R., additional, Müller, D., additional, St Cyr, O. C., additional, Auchère, F., additional, Berghmans, D., additional, Fludra, A., additional, Horbury, T. S., additional, Howard, R. A., additional, Krucker, S., additional, Maksimovic, M., additional, Owen, C. J., additional, Rodríguez-Pacheco, J., additional, Romoli, M., additional, Solanki, S. K., additional, Watson, C., additional, Sanchez, L., additional, Lefort, J., additional, Osuna, P., additional, Gilbert, H. R., additional, Nieves-Chinchilla, T., additional, Abbo, L., additional, Alexandrova, O., additional, Anastasiadis, A., additional, Andretta, V., additional, Antonucci, E., additional, Appourchaux, T., additional, Aran, A., additional, Arge, C. N., additional, Aulanier, G., additional, Baker, D., additional, Bale, S. D., additional, Battaglia, M., additional, Bellot Rubio, L., additional, Bemporad, A., additional, Berthomier, M., additional, Bocchialini, K., additional, Bonnin, X., additional, Brun, A. S., additional, Bruno, R., additional, Buchlin, E., additional, Büchner, J., additional, Bucik, R., additional, Carcaboso, F., additional, Carr, R., additional, Carrasco-Blázquez, I., additional, Cecconi, B., additional, Cernuda Cangas, I., additional, Chen, C. H. K., additional, Chitta, L. P., additional, Chust, T., additional, Dalmasse, K., additional, D’Amicis, R., additional, Da Deppo, V., additional, De Marco, R., additional, Dolei, S., additional, Dolla, L., additional, Dudok de Wit, T., additional, van Driel-Gesztelyi, L., additional, Eastwood, J. P., additional, Espinosa Lara, F., additional, Etesi, L., additional, Fedorov, A., additional, Félix-Redondo, F., additional, Fineschi, S., additional, Fleck, B., additional, Fontaine, D., additional, Fox, N. J., additional, Gandorfer, A., additional, Génot, V., additional, Georgoulis, M. K., additional, Gissot, S., additional, Giunta, A., additional, Gizon, L., additional, Gómez-Herrero, R., additional, Gontikakis, C., additional, Graham, G., additional, Green, L., additional, Grundy, T., additional, Haberreiter, M., additional, Harra, L. K., additional, Hassler, D. M., additional, Hirzberger, J., additional, Ho, G. C., additional, Hurford, G., additional, Innes, D., additional, Issautier, K., additional, James, A. W., additional, Janitzek, N., additional, Janvier, M., additional, Jeffrey, N., additional, Jenkins, J., additional, Khotyaintsev, Y., additional, Klein, K.-L., additional, Kontar, E. P., additional, Kontogiannis, I., additional, Krafft, C., additional, Krasnoselskikh, V., additional, Kretzschmar, M., additional, Labrosse, N., additional, Lagg, A., additional, Landini, F., additional, Lavraud, B., additional, Leon, I., additional, Lepri, S. T., additional, Lewis, G. R., additional, Liewer, P., additional, Linker, J., additional, Livi, S., additional, Long, D. M., additional, Louarn, P., additional, Malandraki, O., additional, Maloney, S., additional, Martinez-Pillet, V., additional, Martinovic, M., additional, Masson, A., additional, Matthews, S., additional, Matteini, L., additional, Meyer-Vernet, N., additional, Moraitis, K., additional, Morton, R. J., additional, Musset, S., additional, Nicolaou, G., additional, Nindos, A., additional, O’Brien, H., additional, Orozco Suarez, D., additional, Owens, M., additional, Pancrazzi, M., additional, Papaioannou, A., additional, Parenti, S., additional, Pariat, E., additional, Patsourakos, S., additional, Perrone, D., additional, Peter, H., additional, Pinto, R. F., additional, Plainaki, C., additional, Plettemeier, D., additional, Plunkett, S. P., additional, Raines, J. M., additional, Raouafi, N., additional, Reid, H., additional, Retino, A., additional, Rezeau, L., additional, Rochus, P., additional, Rodriguez, L., additional, Rodriguez-Garcia, L., additional, Roth, M., additional, Rouillard, A. P., additional, Sahraoui, F., additional, Sasso, C., additional, Schou, J., additional, Schühle, U., additional, Sorriso-Valvo, L., additional, Soucek, J., additional, Spadaro, D., additional, Stangalini, M., additional, Stansby, D., additional, Steller, M., additional, Strugarek, A., additional, Štverák, Š., additional, Susino, R., additional, Telloni, D., additional, Terasa, C., additional, Teriaca, L., additional, Toledo-Redondo, S., additional, del Toro Iniesta, J. C., additional, Tsiropoula, G., additional, Tsounis, A., additional, Tziotziou, K., additional, Valentini, F., additional, Vaivads, A., additional, Vecchio, A., additional, Velli, M., additional, Verbeeck, C., additional, Verdini, A., additional, Verscharen, D., additional, Vilmer, N., additional, Vourlidas, A., additional, Wicks, R., additional, Wimmer-Schweingruber, R. F., additional, Wiegelmann, T., additional, Young, P. R., additional, and Zhukov, A. N., additional

Published
2020
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19. The Solar Orbiter Heliospheric Imager (SoloHI)

Author

Howard, R. A., primary, Vourlidas, A., additional, Colaninno, R. C., additional, Korendyke, C. M., additional, Plunkett, S. P., additional, Carter, M. T., additional, Wang, D., additional, Rich, N., additional, Lynch, S., additional, Thurn, A., additional, Socker, D. G., additional, Thernisien, A. F., additional, Chua, D., additional, Linton, M. G., additional, Koss, S., additional, Tun-Beltran, S., additional, Dennison, H., additional, Stenborg, G., additional, McMullin, D. R., additional, Hunt, T., additional, Baugh, R., additional, Clifford, G., additional, Keller, D., additional, Janesick, J. R., additional, Tower, J., additional, Grygon, M., additional, Farkas, R., additional, Hagood, R., additional, Eisenhauer, K., additional, Uhl, A., additional, Yerushalmi, S., additional, Smith, L., additional, Liewer, P. C., additional, Velli, M. C., additional, Linker, J., additional, Bothmer, V., additional, Rochus, P., additional, Halain, J.-P., additional, Lamy, P. L., additional, Auchère, F., additional, Harrison, R. A., additional, Rouillard, A., additional, Patsourakos, S., additional, Cyr, O. C. St., additional, Gilbert, H., additional, Maldonado, H., additional, Mariano, C., additional, and Cerullo, J., additional

Published
2020
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27. Radio Tracking of a White-Light CME from Solar Corona to Interplanetary Medium

Author

Reiner, M. J, Kaiser, Michael L, Plunkett, S. P, and Prestage, N. P

Subjects
Solar Physics
Abstract

We analyze the radio emissions associated with a flare/CME event on the sun. For this solar event there were type II radio emissions observed in both the metric and decametric to kilometric wavelength regimes. By comparing the dynamics of the CME with that implied by the frequencies and frequency-drift rates of the type II radio emissions, it is concluded that only the decametric/kilometric type II radio emissions are associated with the CME. We provide the first direct one-to-one comparison between a CME and the associated type II radio emissions. The dynamics implied by the metric type II radio emissions suggest a distinct coronal shock, associated with the flare, which only produces radio emissions in the low corona.

Published
1999

28. White-light coronal mass ejections: A new perspective from LASCO

Author

St.Cyr, O. C, Howard, R. A, Simnett, G. M, Gurman, J. B, Plunkett, S. P, Sheeley, N. R., Jr, Schwenn, R, Koomen, M. J, Brueckner, G. E, Michels, D. J, Andrews, M, Biesecker, D. A, Cook, J, Dere, K. P, Duffin, R, Einfalt, E, Korendyke, C. M, Lamy, P. L, Lewis, D, and Llebaria, A

Subjects
Solar Physics
Abstract

More than 275 coronal mass ejections (CMEs) were recorded by the large angle spectroscopic coronagraph (LASCO) from January 1996 through August 1997. Some of the characteristics of 65 of these CMEs, occurring during a three month period (May to July 1997) were quantified. During this time the rate of CME detection was about 0.7 CMEs per day; the distribution of apparent latitudes was clustererd near the equator with an average latitude of 3 deg N; the average width of the CMEs was 49 deg; and the average speed was 324 km/s. The statistical measures and the distributions for these CMEs agree with the existing literature. One new result was the high fraction (plus or minus 35 deg) of CMEs with at least one concave-outward morphological feature, which was considered a possible signature of magnetic disconnection. A new small-scale phenomenon that appears to be the white light counterpart of the extreme ultraviolet microjets detected in the polar coronal holes is described.

Published
1997

29. A multi-wavelength analysis of the February 6/7, 1997 coronal mass ejection

Author

Plunkett, S. P, Gopalswamy, N, Kundu, M. R, Howard, R. A, Thompson, B. J, Gurman, J. B, Lepping, R. P, Hudson, H. S, Nitta, N, Hanaoka, Y, Kosugi, T, and Burkpile, J. T

Subjects
Solar Physics
Abstract

The coronal mass ejection (CME) event on 6 to 7 February 1997 that originate from the southwest quadrant of the sun are analyzed. The CME is accelerated from a projected speed of 170 km/s to about 650 km/s at 25 solar radii. The CME is an arcade eruption followed by bright prominence core structures. The CME was accompanied by an arcade formation. The X-ray and extreme ultraviolet observations suggest that the reconnection proceeded from the northwest and the southeast end of a filament channel. The CME event caused interplanetary effects that produced a medium size geomagnetic storm on earth. Issues relating to the origin and propagation of geo-effective solar disturbances are addressed.

Published
1997

30. Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI)

Author

Howard, R. A., primary, Moses, J. D., additional, Vourlidas, A., additional, Newmark, J. S., additional, Socker, D. G., additional, Plunkett, S. P., additional, Korendyke, C. M., additional, Cook, J. W., additional, Hurley, A., additional, Davila, J. M., additional, Thompson, W. T., additional, St Cyr, O. C., additional, Mentzell, E., additional, Mehalick, K., additional, Lemen, J. R., additional, Wuelser, J. P., additional, Duncan, D. W., additional, Tarbell, T. D., additional, Wolfson, C. J., additional, Moore, A., additional, Harrison, R. A., additional, Waltham, N. R., additional, Lang, J., additional, Davis, C. J., additional, Eyles, C. J., additional, Mapson-Menard, H., additional, Simnett, G. M., additional, Halain, J. P., additional, Defise, J. M., additional, Mazy, E., additional, Rochus, P., additional, Mercier, R., additional, Ravet, M. F., additional, Delmotte, F., additional, Auchere, F., additional, Delaboudiniere, J. P., additional, Bothmer, V., additional, Deutsch, W., additional, Wang, D., additional, Rich, N., additional, Cooper, S., additional, Stephens, V., additional, Maahs, G., additional, Baugh, R., additional, McMullin, D., additional, and Carter, T., additional

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31. The Extreme Solar Storms of October to November 2003

Author

NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV, Plunkett, S. P., NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV, and Plunkett, S. P.

Abstract

In recent decades, humans have come to rely on space technology for an ever-increasing variety of purposes, including human exploration of the solar system, scientific research, national defense, and commercial activities. The field of space weather seeks to understand and predict variability in the space environment. The Sun is the source of all space weather, and the origins of major space weather storms can be traced to explosive releases of magnetic energy from the solar atmosphere in the form of solar flares and coronal mass ejections (CMEs). A solar flare occurs when a sudden release of energy in an active region of the solar atmosphere leads to rapid heating of a localized region of the atmosphere, and rapid acceleration of charged particles to relativistic energies. A CME involves the expulsion of large amounts of ionized plasma and magnetic field from the Sun into interplanetary space (Fig. 1). A typical CME involves the ejection of about 10(13) kg of plasma, at speeds from a few hundred km/s up to a few thousand km/s, into interplanetary space. A major scientific objective of contemporary research in solar-terrestrial physics is to understand how and why these events occur on the Sun, and how to predict their occurrence and their effects on humans in space and on technological systems both in space and on the ground., Published in Naval Research Laboratory (NRL) Review, p91-98, 2005.

Published
2005

34. Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI)

Author

Howard, R. A., primary, Moses, J. D., additional, Vourlidas, A., additional, Newmark, J. S., additional, Socker, D. G., additional, Plunkett, S. P., additional, Korendyke, C. M., additional, Cook, J. W., additional, Hurley, A., additional, Davila, J. M., additional, Thompson, W. T., additional, St Cyr, O. C., additional, Mentzell, E., additional, Mehalick, K., additional, Lemen, J. R., additional, Wuelser, J. P., additional, Duncan, D. W., additional, Tarbell, T. D., additional, Wolfson, C. J., additional, Moore, A., additional, Harrison, R. A., additional, Waltham, N. R., additional, Lang, J., additional, Davis, C. J., additional, Eyles, C. J., additional, Mapson-Menard, H., additional, Simnett, G. M., additional, Halain, J. P., additional, Defise, J. M., additional, Mazy, E., additional, Rochus, P., additional, Mercier, R., additional, Ravet, M. F., additional, Delmotte, F., additional, Auchere, F., additional, Delaboudiniere, J. P., additional, Bothmer, V., additional, Deutsch, W., additional, Wang, D., additional, Rich, N., additional, Cooper, S., additional, Stephens, V., additional, Maahs, G., additional, Baugh, R., additional, McMullin, D., additional, and Carter, T., additional

Published
2008
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35. Heliospheric Images of the Solar Wind at Earth

Author

Sheeley, Jr., N. R., primary, Herbst, A. D., additional, Palatchi, C. A., additional, Wang, Y.‐M., additional, Howard, R. A., additional, Moses, J. D., additional, Vourlidas, A., additional, Newmark, J. S., additional, Socker, D. G., additional, Plunkett, S. P., additional, Korendyke, C. M., additional, Burlaga, L. F., additional, Davila, J. M., additional, Thompson, W. T., additional, St Cyr, O. C., additional, Harrison, R. A., additional, Davis, C. J., additional, Eyles, C. J., additional, Halain, J. P., additional, Wang, D., additional, Rich, N. B., additional, Battams, K., additional, Esfandiari, E., additional, and Stenborg, G., additional

Published
2008
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36. SECCHI Observations of the Sun's Garden-Hose Density Spiral

Author

Sheeley, Jr., N. R., primary, Herbst, A. D., additional, Palatchi, C. A., additional, Wang, Y.-M., additional, Howard, R. A., additional, Moses, J. D., additional, Vourlidas, A., additional, Newmark, J. S., additional, Socker, D. G., additional, Plunkett, S. P., additional, Korendyke, C. M., additional, Burlaga, L. F., additional, Davila, J. M., additional, Thompson, W. T., additional, St Cyr, O. C., additional, Harrison, R. A., additional, Davis, C. J., additional, Eyles, C. J., additional, Halain, J. P., additional, Wang, D., additional, Rich, N. B., additional, Battams, K., additional, Esfandiari, E., additional, and Stenborg, G., additional

Published
2008
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40. LASCO Observations of Disconnected Magnetic Structures Out to Beyond 28 Solar Radii During Coronal Mass Ejections

Author

BIRMINGHAM UNIV (UNITED KINGDOM) SCHOOL OF PHYSICS AND SPACE RESEARCH, Simnett, G. M., Tappin, S. J., Plunkett, S. P., Bedford, D. K., Eyles, C. J., St. Cyr, O. C., Howard, R. A., Brueckner, G. E., Michels, D. J., Moses, J. D., BIRMINGHAM UNIV (UNITED KINGDOM) SCHOOL OF PHYSICS AND SPACE RESEARCH, Simnett, G. M., Tappin, S. J., Plunkett, S. P., Bedford, D. K., Eyles, C. J., St. Cyr, O. C., Howard, R. A., Brueckner, G. E., Michels, D. J., and Moses, J. D.

Abstract

Two coronal mass ejections have been well observed by the LASCO coronagraphs to move out into the interplanetary medium as disconnected plasmoids. The first, on July 28, 1996, left the Sun above the west limb around 18:00 UT. As it moved out, a bright V-shaped structure was visible in the C2 coronagraph which moved into the field-of-view of C3 and could be observed out to beyond 28 solar radii. The derived average velocity in the plane of the sky was 110 plus or minus km s(-1) out to 5 solar radii, and above 15 solar radii the velocity was 269 10 km s(-1). Thus there is evidence of some acceleration around 6 solar radii. The second event occurred on November 5, 1996 and left the west limb around 04:00 UT. The event had an average velocity in the plane of the sky of approx. 54 km s(-1) below 4 R, and it accelerated rapidly around 5 R up to 310 plus or minus 10 km s(-1). In both events the rising plasmoid is connected back to the Sun by a straight, bright ray, which is probably a signature of a neutral sheet. In the November event there is evidence for multiple plasmoid ejections. The acceleration of the plasmoids around a projected altitude of 5 solar radii is probably a manifestation of the source surface of the solar wind., Published in Solar Physics, v175 p685-698, 1997.

Published
1997

47. What is the source of the magnetic helicity shed by CMEs? The long-term helicity budget of AR 7978

Author

Démoulin, P., Mandrini, C. H., van Driel-Gesztelyi, L., Thompson, B. J., Plunkett, S., Kővári, Zs., Aulanier, G., Young, A., Démoulin, P., Mandrini, C. H., van Driel-Gesztelyi, L., Thompson, B. J., Plunkett, S., Kővári, Zs., Aulanier, G., and Young, A.

Abstract

An isolated active region (AR) was observed on the Sun during seven rotations, starting from its birth in July 1996 to its full dispersion in December 1996. We analyse the long-term budget of the AR relative magnetic helicity. Firstly, we calculate the helicity injected by differential rotation at the photospheric level using MDI/SoHO magnetograms. Secondly, we compute the coronal magnetic field and its helicity selecting the model which best fits the soft X-ray loops observed with SXT/Yohkoh. Finally, we identify all the coronal mass ejections (CMEs) that originated from the AR during its lifetime using LASCO and EIT/SoHO. Assuming a one to one correspondence between CMEs and magnetic clouds, we estimate the magnetic helicity which could be shed via CMEs. We find that differential rotation can neither provide the required magnetic helicity to the coronal field (at least a factor 2.5 to 4 larger), nor to the field ejected to the interplanetary space (a factor 4 to 20 larger), even in the case of this AR for which the total helicity injected by differential rotation is close to the maximum possible value. However, the total helicity ejected is equivalent to that of a twisted flux tube having the same magnetic flux as the studied AR and a number of turns in the interval $[0.5,2.0]$. We suggest that the main source of helicity is the inherent twist of the magnetic flux tube forming the active region. This magnetic helicity is transferred to the corona either by the continuous emergence of the flux tube for several solar rotations (i.e. on a time scale much longer than the classical emergence phase), or by torsional Alfvén waves.

Published
2002
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50. Properties of coronal mass ejections: SOHO LASCO observations from January 1996 to June 1998

Author

St. Cyr, O. C., primary, Howard, R. A., additional, Sheeley, N. R., additional, Plunkett, S. P., additional, Michels, D. J., additional, Paswaters, S. E., additional, Koomen, M. J., additional, Simnett, G. M., additional, Thompson, B. J., additional, Gurman, J. B., additional, Schwenn, R., additional, Webb, D. F., additional, Hildner, E., additional, and Lamy, P. L., additional

Published
2000
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