- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Triggering Mechanism and Material Transfer of a Failed Solar Filament Eruption
摘要： Solar ?lament eruptions are often associated with solar ?ares and coronal mass ejections, which have the greatest impact on space weather. However, the ?ne structures and the trigger mechanisms of solar ?laments are still unclear. To address these issues, we studied a failed solar active-region ?lament eruption associated with a C-class ?are by using high-resolution Hα images from the New Vacuum Solar Telescope, supplemented by EUV observations from the Solar Dynamics Observatory. Before the ?lament eruption, a small bipolar magnetic ?eld emerged below the ?lament. Then magnetic reconnection between the ?lament and the emerging bipolar magnetic ?eld triggered the ?lament eruption. During the ?lament eruption, the untwisting motion of the ?lament can be clearly traced by the eruptive threads. Moreover, the footpoints of the eruptive threads are determined by tracing the descending ?lament material. Note that the twisted structure of the ?lament and the right part of the eruptive ?lament threads cannot be seen before the ?lament eruption. These eruptive threads in the right part of the ?lament are found to be rooting in the weak negative polarities near the main negative sunspot. Moreover, a new ?lament formed in the ?lament channel due to material injection from the eruptive ?lament. The above observations and the potential ?eld extrapolations are inclined to support the idea that the ?lament materials were transferred into the overlying magnetic loops and the nearby ?lament channel by magnetic reconnection. These observations improve our understanding of the complexity of ?lament eruptions.
关键词： Solar activity,Solar magnetic ?elds,Solar magnetic reconnection,Sunspots,Solar active region magnetic ?elds,Solar ?lament eruptions,Solar active region ?laments,Solar ?ares,Solar physics,Solar atmosphere
更新于2025-09-23 15:19:57
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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Sub-terahertz Quantum-cascade Laser Source based on Difference-frequency Generation
摘要： Authors report a sub-terahertz monolithic semiconductor source based on a high power, long-wavelength quantum cascade laser. In order to obtain higher nonlinear susceptibility in the sub-terahertz frequency region, we design long wavelength dual-upper-state active region in which transition dipole moments are substantially increased. A fabricated device with distributed feedback grating produces nearly watt-level infrared output power, and as a result, it exhibits a peak output power of 18.5 μW at room temperature, around a frequency of ~700 GHz. Besides, the device produces an output power of 103 μW at 110 K.
关键词： dual-upper-state active region,monolithic semiconductor source,difference-frequency generation,sub-terahertz,quantum-cascade laser
更新于2025-09-16 10:30:52
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The Effect of Active Region Heating on Dynamic and Power Characteristics of Quantum Cascade Lasers Emitting at a Wavelength of 4.8 μm at Room Temperature
摘要： Results of studying stripe quantum cascade lasers emitting at room temperature in the spectral range of 4.8 μm are presented. Power characteristics and turn-on dynamics of the lasers upon pulse pumping are studied. The performed investigations demonstrate the presence of a significant heating of the active region during the pump pulse.
关键词： active region,pump pulse,heterostructure
更新于2025-09-16 10:30:52
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Identification of photospheric activity features from SOHO/MDI data using the ASAP tool
摘要： The variation of solar irradiance is one of the natural forcing mechanisms of the terrestrial climate. Hence, the time-dependent solar irradiance is an important input parameter for climate modelling. The solar surface magnetic field is a powerful proxy for solar irradiance reconstruction. The analyses of data obtained with the Michelson Doppler Imager (MDI) on board the SOHO mission are therefore useful for the identification of solar surface magnetic features to be used in solar irradiance reconstruction models. However, there is still a need for automated technologies that would enable the identification of solar activity features from large databases. To achieve this we present a series of enhanced segmentation algorithms developed to detect and calculate the area coverages of specific magnetic features from MDI intensitygrams and magnetograms. These algorithms are part of the Automated Solar Activity Prediction (ASAP) tool. The segmentation algorithms allow us to identify the areas on the solar disk covered by magnetic elements inside and outside boundaries of active regions. Depending on their contrast properties, magnetic features within an active region boundary are classified as sunspot umbra and penumbra, or faculae. Outside an active region boundary magnetic elements are identified as network. We present the detailed steps involved in the segmentation process and provide the area coverages of the segmented MDI intensitygrams and magnetograms. The feature segmentation was carried out on daily intensitygrams and magnetograms from April 21, 1996 to April 11, 2011. This offers an exciting opportunity to undertake further investigations that benefit from solar features segmentations, such as solar irradiance reconstruction, which we plan to investigate in the future.
关键词： Magnetogram,Sunspot,Solar image processing,Spectral irradiance,Active region
更新于2025-09-04 15:30:14