8 results on '"Farrugia, Charles J."'
Search Results
2. Multi‐Scale Observation of Magnetotail Reconnection Onset: 2. Microscopic Dynamics.
- Author
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Genestreti, Kevin J., Farrugia, Charles J., Lu, San, Vines, Sarah K., Reiff, Patricia H., Phan, Tai, Baker, Daniel N., Leonard, Trevor W., Burch, James L., Bingham, Samuel T., Cohen, Ian J., Shuster, Jason R., Gershman, Daniel J., Mouikis, Christopher G., Rogers, Anthony J., Torbert, Roy B., Trattner, Karlheinz J., Webster, James M., Chen, Li‐Jen, and Giles, Barbara L.
- Subjects
CURRENT sheets ,MAGNETIC reconnection ,WIND pressure ,ELECTRIC fields ,MAGNETIC fields ,SOLAR wind ,LATITUDE ,MOUTH protectors - Abstract
We analyze the local dynamics of magnetotail reconnection onset using Magnetospheric Multiscale (MMS) data. In conjunction with MMS, the macroscopic dynamics of this event were captured by a number of other ground and space‐based observatories, as is reported in a companion paper. We find that the local dynamics of the onset were characterized by the rapid thinning of the cross‐tail current sheet below the ion inertial scale, accompanied by the growth of flapping waves and the subsequent onset of electron tearing. Multiple kinetic‐scale magnetic islands were detected coincident with the growth of an initially sub‐Alfvénic, demagnetized tailward ion exhaust. The onset and rapid enhancement of parallel electron inflow at the exhaust boundary was a remote signature of the intensification of reconnection Earthward of the spacecraft. Two secondary reconnection sites are found embedded within the exhaust from a primary X‐line. The primary X‐line was designated as such on the basis that (a) while multiple jet reversals were observed in the current sheet, only one reversal of the electron inflow was observed at the high‐latitude exhaust boundary, (b) the reconnection electric field was roughly five times larger at the primary X‐line than the secondary X‐lines, and (c) energetic electron fluxes increased and transitioned from anti‐field‐aligned to isotropic during the primary X‐line crossing, indicating a change in magnetic topology. The results are consistent with the idea that a primary X‐line mediates the reconnection of lobe magnetic field lines and accelerates electrons more efficiently than its secondary X‐line counterparts. Key Points: Magnetotail reconnection onset was triggered by electron tearing during a solar wind pressure pulseOnset was characterized by the rapid collapse of the current sheet thickness and kinetic‐scale flux rope formationA primary X‐line was established within minutes of the onset [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Multiscale Observation of Magnetotail Reconnection Onset: 1. Macroscopic Dynamics.
- Author
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Genestreti, Kevin J., Farrugia, Charles J., Lu, San, Vines, Sarah K., Reiff, Patricia H., Phan, Tai, Baker, Daniel N., Leonard, Trevor W., Burch, James L., Bingham, Samuel T., Cohen, Ian J., Shuster, Jason R., Gershman, Daniel J., Mouikis, Christopher G., Rogers, Anthony J., Torbert, Roy B., Trattner, Karlheinz J., Webster, James M., Chen, Li‐Jen, and Giles, Barbara L.
- Subjects
CURRENT sheets ,WIND pressure ,SOLAR wind ,METEOROLOGICAL satellites ,SOLAR system - Abstract
We analyze a magnetotail reconnection onset event on 3 July 2017 that was observed under otherwise quiescent magnetospheric conditions by a fortuitous conjunction of six space and ground‐based observatories. The study investigates the large‐scale coupling of the solar wind–magnetosphere system that precipitated the onset of the magnetotail reconnection, focusing on the processes that thinned and stretched the cross‐tail current layer in the absence of significant flux loading during a 2‐hr‐long preconditioning phase. It is demonstrated with data in the (a) upstream solar wind, (b) at the low‐latitude magnetopause, (c) in the high‐latitude polar cap, and (d) in the magnetotail that the typical picture of solar wind‐driven current sheet thinning via flux loading does not appear relevant for this particular event. We find that the current sheet thinning was, instead, initiated by a transient solar wind pressure pulse and that the current sheet thinning continued even as the magnetotail and solar wind pressures decreased. We suggest that field line curvature‐induced scattering (observed by magnetospheric multiscale) and precipitation (observed by Defense Meteorological Satellite Program) of high‐energy thermal protons may have evacuated plasma sheet thermal energy, which may require a thinning of the plasma sheet to preserve pressure equilibrium with the solar wind. Key Points: Magnetotail reconnection onset was observed during a fortuitous multiscale conjunction of the heliophysics observatoriesA transient solar wind pressure pulse triggered thinning and stretching of the cross‐tail current sheet without significant flux loadingA second solar wind pressure pulse caused the thinned current sheet to rapidly collapse and reconnect [ABSTRACT FROM AUTHOR]
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- 2023
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4. Evolution of the Radial Size and Expansion of Coronal Mass Ejections Investigated by Combining Remote and In-Situ Observations
- Author
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Zhuang, Bin, Lugaz, Noé, Al-Haddad, Nada, Winslow, Réka M., Scolini, Camilla, Farrugia, Charles J., and Galvin, Antoinette B.
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Astrophysics - Solar and Stellar Astrophysics ,Physics - Space Physics ,FOS: Physical sciences ,Solar and Stellar Astrophysics (astro-ph.SR) ,Space Physics (physics.space-ph) - Abstract
A fundamental property of coronal mass ejections (CMEs) is their radial expansion, which determines the increase in the CME radial size and the decrease in the CME magnetic field strength as the CME propagates. CME radial expansion can be investigated either by using remote observations or by in-situ measurements based on multiple spacecraft in radial conjunction. However, there have been only few case studies combining both remote and in-situ observations. It is therefore unknown if the radial expansion estimated remotely in the corona is consistent with that estimated locally in the heliosphere. To address this question, we first select 22 CME events between the years 2010 and 2013, which were well observed by coronagraphs and by two or three spacecraft in radial conjunction. We use the graduated cylindrical shell model to estimate the radial size, radial expansion speed, and a measure of the dimensionless expansion parameter of CMEs in the corona. The same parameters and two additional measures of the radial-size increase and magnetic-field-strength decrease with heliocentric distance of CMEs based on in-situ measurements are also calculated. For most of the events, the CME radial size estimated by remote observations is inconsistent with the in-situ estimates. We further statistically analyze the correlations of these expansion parameters estimated using remote and in-situ observations, and discuss the potential reasons for the inconsistencies and their implications for the CME space weather forecasting., Accepted by ApJ
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- 2023
5. A friend in need: ICA and the National Archives of Malta.
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Farrugia, Charles J.
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NATIONAL archives - Abstract
As any other NGO the ICA offers several benefits to its members. When one goes on the publicity literature of the organization, emphasis is made on the provision of a network of colleagues, specialized advice, and a tool kit of products and publications that come out of the organization. These are all noble benefits. But there are other political, psychological, and intangible benefits that such a network offers. This article celebrates the contribution of Charles Kecskemeti to the international archival domain through some personal reflections of what ICA membership has meant for Malta, for our National Archives and for me personally as an archivist. [ABSTRACT FROM AUTHOR]
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- 2022
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6. Impulse-driven oscillations of the near-Earth's magnetosphere.
- Author
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Sato, Hiroatsu, Pécseli, Hans L., Trulsen, Jan K., Sandholt, Per Even, and Farrugia, Charles J.
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MAGNETOSPHERE ,RADIATION belts ,ELECTRIC fields ,MAGNETIC fields ,SOLAR wind ,EARTH (Planet) - Abstract
It is argued that a simple model based on magnetic image arguments suffices to give a convincing insight into both the basic static as well as dynamic properties of the near-Earth's magnetosphere. Qualitative results can be obtained for the heating due to the compression of the radiation belts. The properties of this simple dynamic model for the solar wind - magnetosphere interaction are discussed and compared to observations. In spite of its simplicity, the model gives convincing results concerning the magnitudes of the near-Earth's magnetic and electric fields. The database contains 5 ground based results for magnetic field variation in response to shocks in the solar wind. The observations also include satellite data, here from the two Van Allen satellites. [ABSTRACT FROM AUTHOR]
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- 2022
- Full Text
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7. Investigating the Cross Sections of Coronal Mass Ejections through the Study of Nonradial Flows with STEREO/PLASTIC.
- Author
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Al-Haddad, Nada, Galvin, Antoinette B., Lugaz, Noé, Farrugia, Charles J., and Yu, Wenyuan
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CORONAL mass ejections ,SOLAR wind ,SOLAR oscillations ,SOLAR cycle ,PLASTICS - Abstract
The solar wind, when measured close to 1 au, is found to flow mostly radially outward. There are, however, periods when the flow makes angles up to 15° away from the radial direction, both in the eastâ€"west and northâ€"south directions. Stream interaction regions (SIRs) are a common cause of eastâ€"west flow deflections. Coronal mass ejections (CMEs) may be associated with nonradial flows in at least two different ways: (1) the deflection of the solar wind in the sheath region, especially close to the magnetic ejecta front boundary, may result in large nonradial flows; and (2) the expansion of the magnetic ejecta may include a nonradial component, which should be easily measured when the ejecta is crossed away from its central axis. In this work, we first present general statistics of nonradial solar wind flows as measured by STEREO/PLASTIC throughout the first 13 yr of the mission, focusing on solar cycle variation. We then focus on the larger deflection flow angles and determine that most of these are associated with SIRs near solar minimum and with CMEs near solar maximum. However, we find no clear evidence of strongly deflected flows, as would be expected if large deflections around the magnetic ejecta or ejecta with elliptical cross sections with large eccentricities were common. We use these results to develop a better understanding of CME expansion and the nature of magnetic ejecta, and point to shortcomings in our understanding of CMEs. [ABSTRACT FROM AUTHOR]
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- 2022
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8. The Handbook of Archival Practice.
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Farrugia, Charles J.
- Subjects
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DIGITAL preservation , *ARCHIVES - Published
- 2022
- Full Text
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