| Validating the Proton Prediction System (PPS) |
DEC 2006 |
8 pages |
| Authors:
S. W. Kahler; E. W. Cliver; A. G. Ling; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
 | The proton prediction system (PPS) is a program developed at the Air Force Research Laboratory (AFRL) to predict solar energetic (E > 5 MeV) proton (SEP) intensities at 1 AU following solar flares. It is based on average observed SEP intensity-time profiles, peak intensities, and event durations. The input parameters are solar flare peak or time-integrated X-ray or radio fluxes and their times of onsets and maxima, and solar flare ... |
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| Reply to the Comment by M. Lockwood et al. on the IDV Index: Its Derivation and Use in Inferring Long-Term Variations |
21 SEP 2006 |
9 pages |
| Authors:
L. Svalgaard; E. W. Cliver; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
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| From an analysis of geomagnetic and solar wind data, Lockwood et al (1999) (hereinafter referred to as LSW99) reported that The solar coronal magnetic field had increased by more than a factor of two during the last century. If true, this would be an important discovery. Recently, Svalgaard and Cliver (2006) (hereinafter referred to as SCOS) reported an analysis based on our newly developed interdiurnal variability (IDV) index of geomagnetic ... |
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| The 1859 Space Weather Event: Then and Now |
2006 |
12 pages |
| Authors:
E. W. Cliver; AIR FORCE RESEARCH LAB HANSCOM AFB MA
|
| The 1859 space weather event, combining the first solar flare ever reported with arguably the largest geomagnetic storm ever observed, provided a dramatic opening to a new area of Sun-Earth studies. Here I describe solar science at the time of the discovery of the flare, recount the observation, and trace the developments that led to the correct interpretation of the 1859 solar-errestrial event by Bartels in 1937. A "fast forward" ... |
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| Introduction to Violent Sun-Earth Connection Events of October-November 2003 |
30 SEP 2005 |
7 pages |
| Authors:
N. Gopalswamy; L. Barbieri; E. W. Cliver; G. Lu; S. P. Plunkett; R. M. Skoug; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| The violent solar eruptions of October-November 2003 are one of the best observed outbreaks of intense solar activity to date. These events, referred to as the Halloween storms, are extreme events in terms of both their source properties at the Sun and their heliospheric consequences. The plasma, particle, and electromagnetic consequences of these events were detected at several locations in the heliosphere thanks to the distributed network of spacecraft. Disturbances ... |
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| On the Origins of Solar EIT Waves |
20 SEP 2005 |
9 pages |
| Authors:
E. W. Cliver; M. Laurenza; M. Storini; B. J. Thompson; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
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| Approximately half of the large-scale coronal waves identified in images obtained by the Extreme-Ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory from 1997 March to 1998 June were associated with small solar flares with soft X-ray intensities below C class. The probability of a given flare of this intensity having an associated EIT wave is low. For example, of ~8,000 B-class flares occurring during this 15 month period, ... |
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| Coronal Shocks of November 1997 Revisited: The CME-Type II Timing Problem |
24 AUG 2004 |
36 pages |
| Authors:
E. W. Cliver; N. V. Nitta; B. J. Thompson; J. Zhang; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| We re-examine observations bearing on the origin of metric type II bursts for six impulsive solar events in November 1997. Previous analyses of these events indicated that the metric type IIs were due to flares (either blast waves or ejecta). Our point of departure was the study of Zhang et al. (2001) based on the Large Angle and Spectrometric Coronagraph's C1 instrument (occulting disk at 1.1 R(sub-O)) that identified the ... |
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| X-Class Soft X-Ray Bursts and Major Proton Events During Solar Cycle 22 (1987-1991). |
05 APR 1994 |
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| Authors:
L. C. Gentile; J. M. Campbell; E. W. Cliver; H. V. Cane; BOSTON COLL CHESTNUT HILL MA INST FOR SPACE RESEARCH
|
 | We compiled a list of all major solar proton events (J(> 10 MeV) > or = 10 pr sq cm s(-1) sr(-1) observed during the first half of Solar Cycle 22 (January 1987 - September 1991) and their flare associations. We also tablulated all X-class soft X-ray bursts observed during this period and studied the intersection of the two data sets. In particular we examined the usefulness of the e-folding ... |
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| Reply. |
04 APR 1994 |
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| Authors:
N. U. Crooker; E. W. Cliver; PHILLIPS LAB HANSCOM AFB MA
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| Gonzalez et al. argue that the postshock Russell-McPherron effect proposed by Crooker et al. (1992) cannot account for the nearly 100% modulation in the semiannual variation of great-storm occurrence because it is too small and because it as often adds to as substracts from the southward component GSE Bsubs of the IMF. We disagree with their conclusion. We use the data of Phillips et al. (1993), who demonstrated the existence ... |
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| Coronal Mass Ejections, Polar Crown Filaments, and Cosmic Ray Modulation, 1979-1989. |
01 APR 1994 |
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| Authors:
E. W. Cliver; O. C. St Cyr; R. A. Howard; P. S. McIntosh; PHILLIPS LAB HANSCOM AFB MA
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| We combined coronagraph observations from Solwind and SMM to obtain Carrington-rotation averages of the daily rate of coronal mass ejection (CMEs), corrected for duty cycle, for the years 1979-1989. We compare these averages with the Deep River galactic cosmic ray (GCR) counting rate, the Ottawa 10.7 cm flux, and the Stanford 'tilt' angle. In early 1982, the long-term (tens of rotations) CME rate changed rapidly (within a solar rotation) from ... |
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| On the Origin of Gamma-Ray Emission From the Behind-the-Limb Flare on 29 September 1989. |
31 MAR 1994 |
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| Authors:
E. W. Cliver; S. W. Kahler; W. T. Vestrand; PHILLIPS LAB HANSCOM AFB MA
|
| Solar gamma-ray line (GRL) emission was observed by the Gamma Ray Spectrometer on SMM in association with a flare behind the west limb on 29 September 1989. We present observations that support a CME-driven coronal shock as a plausible source of the energetic protons that produced the GRL emission on the visible disk. |
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| A Seasonal Dependence for the Geoeffectiveness of Eruptive Solar Events. |
31 MAR 1994 |
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| Authors:
E. W. Cliver; N. U. Crooker; PHILLIPS LAB HANSCOM AFB MA
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| The pronounced seasonal variation of the occurrence rate of great geomagnetic storms, attributed to in-ecliptic draping of interplanetary magnetic fields and the Russell-McPherron effect, suggests that the geoeffectiveness of the causative eruptive solar events has a seasonal dependence. Thus an eruptive solar event of a given 'size' occurring near the equinoxes might be expected to give rise to a larger geomagnetic storm than would a comparable event occurring near the ... |
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| Superevents and Cosmic Ray Modulation, 1974-1985 |
01 SEP 1993 |
12 pages |
| Authors:
E. W. Cliver; W. Droge; R. Muller-Mellin; PHILLIPS LAB HANSCOM AFB MA
|
| Superevents are long-lived proton events that originate in episodes of intense solar activity characterized by major coronal mass ejection (CMEs) and individual solar energetic particle events. Superevents exhibit only weak intensity variation with heliolongitude. They propagate to the outer heliosphere at speeds above that of the average solar wind, and at Pioneers 10 and 11, prominent superevents are generally associated with strong interplanetary shocks. From 1974 to 1985, we find ... |
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| On the Origin of Gamma-Ray Emission From the Behind-the-Limb Flare on 29 September 1989 |
30 JUL 1993 |
4 pages |
| Authors:
E. W. Cliver; S. W. Kahler; W. T. Vestrand; PHILLIPS LAB HANSCOM AFB MA
|
| Solar gamma-ray line (GRL) emission was observed by the Gamma Ray Spectrometer on SMM in association with a flare behind the west limb on 29 September 1989. We present observations that support a CME-driven coronal shock as a plausible source of the energetic protons that produced the GRL emission on the visible disk. Gamma-rays, Solar flares, Solar energetic particles. |
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| A Correlation Between 4-8 MeV Gamma-Ray-Line Fluence and > 50 Kev X-Ray Fluence in Large Solar Flares |
1993 |
8 pages |
| Authors:
E. W. Cliver; N. B. Crosby; B. R. Dennis; PHILLIPS LAB HANSCOM AFB MA
|
| For large flares observed by the Solar Maximum Mission (SMM) satellite from 1980-1982, we find a reasonably good correlation between 4-8 MeV gamma-ray-line (GRL) fluences and >50 keV hard X-ray fluences. We find no compelling evidence for a distinct population of large hard X-ray flares that lack commensurate GRL emission. Our results are consistent with the acceleration of the bulk of the approx. 100 keV electrons and approx. 10 MeV ... |
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| The Propagation of Super-Events from 03-35 AU, |
03 AUG 1992 |
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| Authors:
W. Droge; R. Muller-Mellin; E. W. Cliver; PHILLIPS LAB HANSCOM AFB MA
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| Super-events are long-lasting enhancements of the interplanetary particle population observed between 0.3 and 35 AU. They appear simultaneously in electrons up to 10 MeV and nucleons up to 70 MeV/N and differ distinctly from known intensity increases due to single solar flare particle events, corotating events, and ESP-events. Their onset and decay is much longer than for flare-associated events, and they remain between two and seven orders of magnitude above ... |
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