Search Publications
Hinode EIS: Updated In-flight Radiometric Calibration
Del Zanna, G.; Warren, H. P.; Weberg, M. J.
We present an update to the in-flight radiometric calibration of the Hinode Extreme Ultraviolet Imaging Spectrometer (EIS), revising and extending our previous studies. We analyze full-spectral EIS observations of quiet Sun (QS) and active regions (ARs) from 2007 until 2022. Using CHIANTI version 10, we adjust the EIS relative effective areas for …
Differentiating the Acceleration Mechanisms in the Slow and Alfvénic Slow Solar Wind
D'Amicis, Raffaella; Reeves, Katharine K.; Stawarz, Julia E. +18 more
In the corona, plasma is accelerated to hundreds of kilometers per second and heated to temperatures hundreds of times hotter than the Sun's surface before it escapes to form the solar wind. Decades of space-based experiments have shown that the energization process does not stop after it escapes. Instead, the solar wind continues to accelerate, a…
Compression method for solar polarization spectra collected from Hinode SOT/SP observations
Oba, T.; Iida, Y.; Iijima, H. +1 more
The rapidly increasing volume of observational solar spectral data poses challenges for efficient and accurate analysis. To address this issue, we present a deep learning-based compression technique using the deep autoencoder (DAE) and 1D-convolutional autoencoder (CAE) models, developed for use on the Hinode SOT/SP data. This technique focuses on…
Detection of a Magnetic Discontinuity in the Upper Solar Chromosphere Associated with a Coronal Loop Brightening Observed by CLASP2.1
Song, Donguk; Rachmeler, Laurel A.; Kobayashi, Ken +15 more
We report the first detection of a magnetic discontinuity in the upper solar chromosphere associated with a coronal loop brightening. Our findings are based on novel observations obtained by the Chromospheric LAyer SpectroPolarimeter (CLASP2.1) suborbital space experiment. During its short 6 minute flight, CLASP2.1 successfully obtained spectropol…
Superstrong Magnetic Fields in Sunspot Bipolar Light Bridges
Solanki, S. K.; Korpi-Lagg, A.; Castellanos Durán, J. S. +2 more
Recent solar observations of bipolar light bridges (BLBs) in sunspots have, in a few individual cases, revealed magnetic fields up to 8.2 kG, which is at least twice as strong as typical values measured in sunspot umbrae. However, the small number of such observations hinted that such strong fields in these bright photospheric features that separa…
Emergence of magnetic flux sheets in the quiet Sun: I. Statistical properties
Guglielmino, S. L.; Ishikawa, R.; Fischer, C. E. +3 more
Context. Small-scale magnetic flux emergence in the quiet Sun is crucial for maintaining solar magnetic activity. On the smallest scales studied so far, namely within individual granules, two mechanisms have been identified: emergence in tiny magnetic loops and emergence in the form of magnetic flux sheets covering the granule. While there are abu…
Derivation and Application of a Scaling between Hinode/SP and SDO/HMI Vector Magnetic Fields to Improve Magnetic Field Extrapolations
Yalim, M. S.; Hu, Q.; Prasad, A. +3 more
Full-disk measurements of the solar magnetic field by the Helioseismic and Magnetic Imager (HMI) are often used for magnetic field extrapolations, but its limited spatial and spectral resolution can lead to significant errors. We compare HMI data with observations of NOAA 12104 by the Hinode Spectropolarimeter (SP) to derive a scaling curve for th…
Elemental Abundances at Coronal Hole Boundaries as a Means to Investigate Interchange Reconnection and the Solar Wind
Koukras, Alexandros; Savin, Daniel W.; Hahn, Michael
The origin of the slow solar wind is not well understood, unlike the fast solar wind that originates from coronal holes. In situ elemental abundances of the slow solar wind suggest that it originates from initially closed field lines that become open. Coronal hole boundary regions are a potential source of slow solar wind, as open field lines ther…
Observed dispersive properties of the slow magnetoacoustic waves propagating in coronal fan loops above sunspots
Zhao, Junwei; Chen, Ruizhu; Wang, Tongjiang
Recurrent and propagating intensity perturbations are frequently observed in extreme ultraviolet (EUV) channels along coronal fan loops above sunspots, and these perturbations are suggested to be slow magnetoacoustic waves. Numerous studies have been conducted to investigate their propagation speeds, damping, and excitation sources; however, there…
Hinode/EIS Observation of the Alfvénic Fluctuations in the Quiet Sun
Young, Peter R.; Morton, Richard; Tajfirouze, Edris
Alfvénic fluctuations in the corona are regularly observed in EUV imaging and infrared spectroscopic data. We report here on the Doppler velocity fluctuations within the data from the Extreme-Ultraviolet Imaging Spectrometer (EIS) on board Hinode. The capabilities of EIS provide an opportunity to detect fluctuations in the solar atmosphere and con…