Xenophon Moussas - Profile on Academia.edu (original) (raw)

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Papers by Xenophon Moussas

Solar Physics, 1983

The north-south asymmetry in the intensity of the 530.3 nm emission coronal line is examined in t... more The north-south asymmetry in the intensity of the 530.3 nm emission coronal line is examined in the time period 1958 to 1980 using data at all latitudes. The results show that overall the northern hemisphere of the Sun is more active in this line. The general pattern has changed after the beginning of the 21st cycle with the southern polar region being more active after the last solar minimum (1975). These anisotropies may be related to phase differences between the activity of northern and southern hemispheres. North-south asymmetries may have implications in the structure and evolution of the heliosphere, its current sheet and even in the cosmic ray propagation.

The Effect of Helio-Geomagnetic Activity on the Proceedings in the Emergency Department of Two Greek Hospitals

Study of the solar and geomagnetic activity influence on the emergency proceedings in Greece, for... more Study of the solar and geomagnetic activity influence on the emergency proceedings in Greece, for selected months of solar cycle 23 and especially for the year 2005 is presented. We examined the time association between the magnetic storms (Dst geomagnetic index), daily numbers of solar flares and Coronal Mass Ejections (CMEs) with the emergency proceedings. The sample of about 30000

Heliomagnetic Latitude Dependence of Cosmic Ray Intensity during the Solar Cycle 21

Energy Balance at the Earth's Magnetosphere

The Breakdown of Diffusive Shock Acceleration Theory in the Relativistic Highly Oblique and Highly Turbulent Limits

Solar Physics

A very smooth and time-invariable bow shock of Mars is revealed using Mars Global Surveyor's data... more A very smooth and time-invariable bow shock of Mars is revealed using Mars Global Surveyor's data. The bow-shock position has been identified using magnetic and electron flux data obtained by the Magnetometer and Electron Reflectometer (MAG/ER) experiment aboard Mars Global Surveyor, in the time period between days 87 and 255 of 1998. From the magnetic field and the electron flux measurements, 148 bow-shock crossings were detected, concentrated mostly on the northern hemisphere of the planet. With these results, a 3D configuration of the bow shock is constructed and presented. The results show that part of the observed bow shock is a surprisingly smooth surface. It is possible that the bow shock is smooth only in the northern hemisphere, since the southern surface is characterized by local magnetic anomalies. Its real shape can only be revealed in a 3D representation in the planetary centered solar ecliptic coordinate system and questions the theoretically expected variation of the bow shock.

Cryovolcanic candidate regions on Titan: Promising landing sites

Study of 40 Solar Energetic Events Based on GOES, LASCO and ARTEMIS IV Data (1998-2000)

Heliomagnetic Latitude Dependence of Cosmic Ray Intensity during the Solar Cycle 21

Energy Balance at the Earth's Magnetosphere

Solar Physics

Study of 40 Solar Energetic Events Based on GOES, LASCO and ARTEMIS IV Data (1998-2000)

Sunspot photometry and area measurements from SOHO/MDI images during the 23rd solar cycle

We present area and photometry measurements of all sunspots (aprox. 12000) for the 23rd solar cyc... more We present area and photometry measurements of all sunspots (aprox. 12000) for the 23rd solar cycle. The images that have been used for our analysis have been taken by the MDI instrument on board So.H.O during the last solar cycle through the years 1997 to 2007. At the completion of our analysis, with a simple algorithm, more than 3.300 images in photometry stage have been used. Initially we determined the sunspot pixel-positions from MDI images and registered them to the data base consisting of a complete record of sunspots during the last cycle, derived from the Mt. Wilson data base. We used a novel algorithm serving the purposes of this analysis, which measures the lowest intensity and the area of every sunspot umbra. Finally, groups penumbral and umbral data will be presented for all sunspot groups.

Sunspot photometry and area measurements from SOHO/MDI images during the 23rd solar cycle

Radio Emission Associated with Solar Energetic Particle Events

The corona probed at meter and decimeter wavelengths is a crucial region for the acceleration and... more The corona probed at meter and decimeter wavelengths is a crucial region for the acceleration and propagation of solar energetic particles (SEPs), and radio diagnostics in this plasma plays a major role in assessing the origin of SEP events. Using data from the ARTEMIS IV solar radio spectro-graph, we report the properties of the radio emission associated with several major SEP events. The association of the radio emission with the related flares and CMEs is also investigated.

Statistics on the Occurrence of Solar Radio Bursts (Type IV and IV) and their Relation with CMEs and Flares Covering the Time Interval 1996-2001 (Rising and Maximum Phase of Solar Cycle 23)

Cassini Scientist for a Day: an international contest in Greece

The international contest 'Cassini Scientist for a Day', organized by the Cassini Outreac... more The international contest 'Cassini Scientist for a Day', organized by the Cassini Outreach team at NASA's Jet Propulsion Laboratory, provides school students all around the world with the opportunity to get involved in astronomy and astrophysics and planetary sciences in particular. It gives excellent opportunity for outreach and publicity for the Cassini mission and ESA and NASA activities in Greece. For the years 2010 and 2011, the Space Physics Group of the Astronomy, Astrophysics and Mechanics section of the University of Athens in association with external colleagues has been selected as the co-ordinator of NASA for the competition in Greece. This kind of school competition in Greece is particularly important since Astronomy and Astrophysics and Space Sciences, although very popular, are not included in the school curricula and thus students rarely have the opportunity to experience and participate actively in these subjects. Under the guidance of Cassini Outreach t...

Radio Emission Associated with Solar Energetic Particle Events

Statistics on the Occurrence of Solar Radio Bursts (Type IV and IV) and their Relation with CMEs and Flares Covering the Time Interval 1996-2001 (Rising and Maximum Phase of Solar Cycle 23)

Solar Physics, 1983

The Effect of Helio-Geomagnetic Activity on the Proceedings in the Emergency Department of Two Greek Hospitals

Heliomagnetic Latitude Dependence of Cosmic Ray Intensity during the Solar Cycle 21

Energy Balance at the Earth's Magnetosphere

The Breakdown of Diffusive Shock Acceleration Theory in the Relativistic Highly Oblique and Highly Turbulent Limits

Solar Physics

Cryovolcanic candidate regions on Titan: Promising landing sites

Study of 40 Solar Energetic Events Based on GOES, LASCO and ARTEMIS IV Data (1998-2000)

Heliomagnetic Latitude Dependence of Cosmic Ray Intensity during the Solar Cycle 21

Energy Balance at the Earth's Magnetosphere

Solar Physics

Study of 40 Solar Energetic Events Based on GOES, LASCO and ARTEMIS IV Data (1998-2000)

Sunspot photometry and area measurements from SOHO/MDI images during the 23rd solar cycle

Radio Emission Associated with Solar Energetic Particle Events

Statistics on the Occurrence of Solar Radio Bursts (Type IV and IV) and their Relation with CMEs and Flares Covering the Time Interval 1996-2001 (Rising and Maximum Phase of Solar Cycle 23)

Cassini Scientist for a Day: an international contest in Greece

Radio Emission Associated with Solar Energetic Particle Events

Statistics on the Occurrence of Solar Radio Bursts (Type IV and IV) and their Relation with CMEs and Flares Covering the Time Interval 1996-2001 (Rising and Maximum Phase of Solar Cycle 23)