scholarly journals Spectroscopic Features in the EUV Emission of a M8 Flare Observed by SUMER

2001 ◽  
Vol 203 ◽  
pp. 260-263 ◽  
Author(s):  
W. Curdt ◽  
E. Landi ◽  
U. Feldman ◽  
D. Innes ◽  
B. Dwivedi ◽  
...  
Keyword(s):  
Active Region ◽  
Atomic Physics ◽  
Temporal Evolution ◽  
Diagnostic Techniques ◽  
Active Region Noaa ◽  
Plasma Diagnostic ◽  
The West ◽  
Euv Emission ◽  
West Limb ◽  
Spectral Scan

A flare of size M8 occurred while SUMER was recording a spectral scan above the active region NOAA 8537 at the west limb. We recorded spectra during the pre-flare phase, at flare onset, and during the decay phase of this main flare in a series of events. More than 60 flare lines were identified during this observation, which include Fe XVIII - Fe XXIII lines that provide evidence of 107 K plasmas. We also recorded lines from He-like ions, such as Ne IX, Na x, Mg XI, and Si XIII. Accurate wavelength measurements of such lines are of interest in basic atomic physics studies. Using plasma diagnostic techniques, we investigated the temporal evolution of the electron densities and temperatures during the event.

scholarly journals RATAN-600 Observations of Unusual Inversion of Polarization in Sunspot Associated Microwave Sources

2005 ◽  
Vol 13 ◽  
pp. 137-137
Author(s):  
N. A. B. Gizani ◽  
C. Alissandrakis ◽  
V. Bogod ◽  
V. Garaimov ◽  
V. Zheleznyakov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Circular Polarization ◽  
Radio Telescope ◽  
The West ◽  
Bipolar Structure ◽  
High Polarization ◽  
West Limb ◽  
Microwave Sources ◽  
The Magnetic Field

We have discovered unusual inversion of circular polarization in both components of an active region. We have observed the region for six consecutive days in May 96 using the RATAN-600 radio telescope with high polarization accuracy up to 0.5 %. The observations were taken in the range of 1.7 to 30 cm. At short wavelengths the circular polarization scans revealed a bipolar structure, expected since the magnetic field is bipolar. However, for all six days and while the region was moving from the center of the disk to the west limb, the circular polarization dropped practically to zero at 14.5 cm and at longer wavelengths the sense of the polarization was reversed.

Quasi Periodic Oscillations in the Pre Phases of Recurrent Jets Highlighting Plasmoids in Current Sheet

2020 ◽  
Author(s):  
Reetika Joshi ◽  
Ramesh Chandra ◽  
Brigitte Schmieder ◽  
Guillaume Aulanier ◽  
Pooja Devi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Current Sheet ◽  
The Other ◽  
Active Region Noaa ◽  
The West ◽  
Periodic Oscillations ◽  
West Limb ◽  
Field Lines ◽  
Open Magnetic Field ◽  
Double Chamber

<p><strong>Solar jets observed at the limb are important to determine the location of reconnection sites in the corona. In this study, we investigate six recurrent hot and cool jets occurring in the active region NOAA 12644 as it is crossing the west limb on April 04, 2017. These jets are observed in all the UV/EUV filters of SDO/AIA and in cooler temperature formation lines in IRIS slit jaw images. The jets are initiated at the top of a double chamber vault with cool loops on one side and hot loops on the other side. The existence of such double chamber vaults suggests the presence of emerging flux with cool loops, the hot loops being the reconnected loops similarly as in the models of Moreno-</strong><strong>Insertis</strong><strong>et al. 2008, 2013 and Nóbrega-Siverio et al. 2016. In the preliminary phase of the main jets, </strong><strong>quasi periodic</strong><strong> intensity oscillations accompanied by smaller jets are detected in the bright current sheet between the vault and the preexisting magnetic field. Individual kernels and plasmoids are ejected in open field lines </strong><strong>along</strong><strong> the jets. Plasmoids may launch torsional Alfven waves and the kernels would be the result of the </strong><strong>untwist</strong><strong> of the plasmoids in open magnetic field as proposed in the model of Wyper et al. 2016.</strong></p>

Morphology of the flare-productive active region NOAA 9087

2020 ◽  
Vol 36 (3) ◽  
pp. 69-90
Author(s):  
S. N. Chornogor ◽  
◽  
N. N. Kondrashova ◽  
Keyword(s):  
Active Region ◽  
Active Region Noaa ◽  
Region Noaa

Characteristics of Soft X-Ray Radiation of the Solar Active Region NOAA 1024 Registered by the PINGVIN-M Device in July 2009

2020 ◽  
Vol 60 (7) ◽  
pp. 936-941
Author(s):  
M. I. Savchenko ◽  
P. V. Vatagin ◽  
P. B. Dmitriev ◽  
M. G. Ogurtsov ◽  
E. M. Kruglov ◽  
...  
Keyword(s):  
Active Region ◽  
Solar Active Region ◽  
Active Region Noaa ◽  
X Ray ◽  
Region Noaa

scholarly journals Magnetic Fields in the Lower Corona Associated with the Expanding Limb Burst On March 30th 1969 Inferred from the Microwave High-Resolution Observations

1971 ◽  
Vol 43 ◽  
pp. 413-416 ◽  
Author(s):  
Shinzo Énomé ◽  
Haruo Tanaka
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Magnetic Fields ◽  
The West ◽  
Lower Corona ◽  
Energetic Electrons ◽  
West Limb ◽  
Flare Region ◽  
Solar Microwave ◽  
Solar Microwave Burst

An expansion of the source of a great solar microwave burst was observed a little beyond the west limb on March 30, 1969. This expansion is interpreted in terms of diffusion of energetic electrons in a turbulent magnetic field in the flare region. The height of the source is estimated to have been 104 km.

The three-dimensional structure of the corona above active region NOAA 9591 from microwave observations

2006 ◽  
Vol 50 (8) ◽  
pp. 679-686 ◽  
Author(s):  
N. G. Peterova ◽  
B. V. Agalakov ◽  
T. P. Borisevich ◽  
A. N. Korzhavin ◽  
B. I. Ryabov
Keyword(s):  
Active Region ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Active Region Noaa ◽  
Three Dimensional Structure ◽  
Region Noaa

Where do running penumbral waves emerge in chromosphere?

2018 ◽  
Vol 13 (S340) ◽  
pp. 155-156
Author(s):  
T. G. Priya ◽  
Jiangtao Su ◽  
Robertus Erd̎elyi
Keyword(s):  
Active Region ◽  
Active Region Noaa ◽  
Long Period ◽  
Wave Guides ◽  
Spiral Structures ◽  
Region Noaa ◽  
Umbral Oscillations

AbstractThe earlier work on the oscillatory phenomena in sunspot structures have supported in validating the detection of long-period oscillations, which are generated by the photospheric umbral response to the five minute p-mode global oscillations. We report here on the events of 3- min umbral oscillations which are detected within a duration of one hour from a single-polarity sunspot of active region NOAA 12132. The umbral oscillations that appear first around umbral boundaries is speculated to be excited by the wavefronts at the umbral-penumbral boundaries due to sub-photospheric or photospheric granular buffetings. The appearance of the wavefronts in spiral structures suggests that the wave guides are twisted. In addition, the newly formed running penumbral waves (RPWs) appears to be connected with the preceding RPWs.

Twist and Writhe of the Magnetic Flux in the Super Active Region NOAA 11429

2014 ◽  
pp. 335-348 ◽  
Author(s):  
A. Elmhamdi ◽  
P. Romano ◽  
A. S. Kordi ◽  
H. A. Al-trabulsy
Keyword(s):  
Active Region ◽  
Magnetic Flux ◽  
Active Region Noaa ◽  
Region Noaa

scholarly journals Control of Tutaabsoluta using pheromone traps on tomato crops under greenhouse in Algeria

2021 ◽  
Vol 16 (1) ◽  
pp. 1-10
Author(s):  
Mohamed Bellatreche ◽  
◽  
Saida Messgo-Moumene ◽  
Atika Guendouz-Ben Rima ◽  
Ikbal Chaieb ◽  
...  
Keyword(s):  
Temporal Evolution ◽  
Integrated Control ◽  
Sustainable Use ◽  
Agricultural Practices ◽  
Pheromone Traps ◽  
The West ◽  
Tomato Production ◽  
Production Areas ◽  
Remarkable Reduction ◽  
Integrated Control System

The present study aimed to assess the effectiveness of pheromone traps of adults of Tuta absoluta in 4 potential tomato production areas in Algeria: Tipaza (Center), Mostaganem (West), Jijel (East) and Biskra (South), during the 2012-2014 campaigns. Two tomato greenhouses were considered for each zone in which, one was protected by the setup of pheromone traps and the other as an insecticide sprayed control. Tomato leaf samples were taken from each greenhouse, each month of each year according to the areas of studies to calculate the rates of infestation. Higher infestation rates were recorded in the greenhouses with local agricultural practices (control) compared with those protected by pheromone traps. With the use of the pheromone traps, a remarkable reduction affected the infestation of the greenhouses in the 4 studied areas during the years 2012 to 2014. The southern area seemed to be the most infested and at a least degree the areas of the West, the Center and the East, respectively. The temporal evolution of infestation rates showed an increase since January until July with June and July showing the higher infestation rates. These results showed the efficacy of trapping of T. absoluta males and the importance of their sustainable use in the integrated control system against this devastating insect in Algeria.

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