English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We analyzed high-cadence sit-and-stare observations acquired with theHinode/EIS spectrometer and HXR measurements acquired with RHESSI during anM-class flare. During the flare impulsive phase, we observe no significantflows in the cooler Fe XIII line but strong upflows, up to 80-150 km/s, in thehotter Fe XVI line. The largest Doppler shifts observed in the Fe XVI line wereco-temporal with the sharp intensity peak. The electron density obtained from aFe XIII line pair ratio exhibited fast increase (within two minutes) from thepre-flare level of 5.01x10^(9) cm^(-3) to 3.16x10^(10) cm^(-3) during the flarepeak. The nonthermal energy flux density deposited from the coronalacceleration site to the lower atmospheric layers during the flare peak wasfound to be 1.34x10^(10) erg/s/cm^(2) for a low-energy cut-off that wasestimated to be 16 keV. During the decline flare phase, we found a secondaryintensity and density peak of lower amplitude that was preceded by upflows of15 km/s that were detected in both lines. The flare was also accompanied by afilament eruption that was partly captured by the EIS observations. We derivedDoppler velocities of 250-300 km/s for the upflowing filament material.Thespectroscopic results for the flare peak are consistent with the scenario ofexplosive chromospheric evaporation, although a comparatively low value of thenonthermal energy flux density was determined for this phase of the flare. Thisoutcome is discussed in the context of recent hydrodynamic simulations. Itprovides observational evidence that the response of the atmospheric plasmastrongly depends on the properties of the electron beams responsible for theheating, in particular the steepness of the energy distribution.

Chromospheric evaporation flows and density changes deduced from Hinode/EIS during an M1.6 flare