Flows and Non-thermal Velocities in Solar Active Regions Observed with the Extreme-ultraviolet Imaging Spectrometer on Hinode: A Tracer of Active Region Sources of Heliospheric Magnetic Fields?

Abstract

From Doppler velocity maps of active regions constructed from spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft we observe large areas of outflow (20-50 km/s) that can persist for at least a day. These outflows occur in areas of active regions that are faint in coronal spectral lines formed at typical quiet Sun and active region temperatures. The outflows are positively correlated with non-thermal velocities in coronal plasmas. The bulk mass motions and non-thermal velocities are derived from spectral line centroids and line widths, mostly from a strong line of Fe XII at 195.12 Angstroms. The electron temperature of the outflow regions estimated from an Fe XIII to Fe XII line intensity ratio is about 1.2-1.4 MK. The electron density of the outflow regions derived from a density sensitive intensity ratio of Fe XII lines is rather low for an active region. Most regions average around 7E10+8 cm(-3), but there are variations on pixel spatial scales of about a factor of 4. We discuss results in detail for two active regions observed by EIS. Images of active regions in line intensity, line width, and line centroid are obtained by rastering the regions. We also discuss data from the active regions obtained from other orbiting spacecraft that support the conclusions obtained from analysis of the EIS spectra. The locations of the flows in the active regions with respect to the longitudinal photospheric magnetic fields suggest that these regions might be tracers of long loops and/or open magnetic fields that extend into the heliosphere, and thus the flows could possibly contribute significantly to the solar wind.

one tex file, 11 postscript figure files

References in corpus (5)

• Ionization balance for optically thin plasmas: rate coefficients for all atoms and ions of the elements H to Ni
• On Solving the Coronal Heating Problem
• Static and Dynamic Modeling of a Solar Active Region. I: Soft X-Ray Emission
• Reappraising Transition Region Line Widths in light of Recent Alfvén Wave Discoveries
• Simple Magnetic Flux Balance as an Indicator of Neon VIII Doppler Velocity Partitioning in an Equatorial Coronal Hole

Cited by in corpus (81)

• MHD Waves and Coronal Seismology: an overview of recent results
• Solar UV and X-Ray Spectral Diagnostics
• Persistent Doppler shift oscillations observed with HINODE/EIS in the solar corona: spectroscopic signatures of Alfvenic waves and recurring upflows
• Full-Sun observations for identifying the source of the slow solar wind
• Establishing a Connection Between Active Region Outflows and the Solar Wind: Abundance Measurements with EIS/Hinode
• What can we learn about solar coronal mass ejections, coronal dimmings, and Extreme-Ultraviolet jets through spectroscopic observations?
• On active region loops: Hinode/EIS observations
• Magnetic Reconnection along Quasi-Separatrix Layers as a Driver of Ubiquitous Active Region Outflows
• Two components of the coronal emission revealed by EUV spectroscopic observations
• Asymmetries of solar coronal extreme ultraviolet emission lines
• The Spectroscopic Signature of Quasi-periodic Upflows in Active Region Timeseries
• Observing Episodic Coronal Heating Events Rooted in Chromospheric Activity
• Multiple Component Outflows in an Active Region Observed with the EUV Imaging Spectrometer on Hinode
• Probing the physics of the solar atmosphere with the Multi-slit Solar Explorer (MUSE): I. Coronal Heating
• Spatially-Resolved Nonthermal Line Broadening During The Impulsive Phase of a Solar Flare
• The Temperature Dependence of Solar Active Region Outflows
• Velocity measurements for a solar active region fan loop from Hinode/EIS observations
• Measurements of Non-Thermal Line Widths in Solar Active Regions
• Flows and Motions in Moss in the Core of a Flaring Active Region: Evidence for Steady Heating
• Upflows in the upper solar atmosphere
• Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares
• Tracking Solar Active Region Outflow Plasma from its Source to the near-Earth Environment
• The coronal source of extreme-ultraviolet line profile asymmetries in solar active region outflows
• EUV spectral line formation and the temperature structure of active region fan loops: observations with Hinode/EIS and SDO/AIA
• High spatial resolution FeXII observations of solar active region
• Coronal Magnetic Field Topology From Total Solar Eclipse Observations
• Outflows at the Edges of an Active Region in a Coronal Hole: A Signature of Active Region Expansion?
• Hot Plasma in Non-Flaring Active Regions Observed by the Extreme-ultraviolet Imaging Spectrometer on Hinode
• Temporal Variability of Active Region Outflows
• Waves in Solar Coronal Loops
• Evidence of Explosive Evaporation in a Microflare Observed by Hinode/EIS
• Evidence of Impulsive Heating in Active Region Core Loops
• Observational Signatures of Waves and Flows in the Solar Corona
• LEMUR: Large European Module for solar Ultraviolet Research. European contribution to JAXA's Solar-C mission
• Spectroscopic Analysis of an EIT Wave/Dimming Observed by Hinode/EIS
• Coronal Behavior Before the Large Flare Onset
• Parallel Evolution of Quasi-separatrix Layers and Active Region Upflows
• The 3D geometry of active region upflows deduced from their limb-to-limb evolution
• Observational Evidence of S-Web Source of the Slow Solar Wind
• Stochastic transients as a source of quasi-periodic processes in the solar atmosphere
• The drivers of active region outflows into the slow solar wind
• Observations of Plasma Upflow in a Warm Loop with Hinode/EIS
• Spectroscopic analysis of interaction between an EIT wave and a coronal upflow region
• On the importance of the nonequilibrium ionization of Si IV and O IV and the line-of-sight in solar surges
• Combining MHD and kinetic modelling of solar flares
• Fan Loops Observed by IRIS, EIS and AIA
• Active Region Moss: Doppler Shifts from Hinode/EIS Observations
• Plasma motions and non-thermal line broadening in flaring twisted coronal loops
• Predicting the COSIE-C Signal from the Outer Corona up to 3 Solar Radii
• Heating and cooling of coronal loops observed by SDO
• Doppler shift of hot coronal lines in a moss area of an active region
• Apparent and Intrinsic Evolution of Active Region Upflows
• IRIS observations of the low-atmosphere counterparts of active region outflows
• Ejection of cool plasma into the hot corona
• Effect of Coronal Loop Structure on Wave Heating by Phase Mixing
• Evolution of active region outflows throughout an active region lifetime
• Non-thermal line broadening due to braiding-induced turbulence in solar coronal loops
• A comparison of the active region upflow and core properties using simultaneous spectroscopic observations from IRIS and Hinode
• On the nature of spectral line broadening in solar coronal dimmings
• Plasma composition measurements in an active region from Solar Orbiter/SPICE and Hinode/EIS
• Observations of Reconnection Flows in a Flare on the Solar Disk
• Polarisation of microwave emission from reconnecting twisted coronal loops
• The Formation and Lifetime of Outflows in a Solar Active Region
• Photospheric Abundances of Polar Jets on the Sun Observed by Hinode
• Widespread Occurrence of High-Velocity Upflows in Solar Active Regions
• EUV Analysis of a Quasi-Static Coronal Loop Structure
• Slow solar wind sources. High-resolution observations with a quadrature view
• Plasma Upflows Induced by Magnetic Reconnection Above an Eruptive Flux Rope
• Magnetic Configurations Related to the Coronal Heating and Solar Wind Generation I. Twist and Expansion Profiles of Magnetic Loops Produced by Flux Emergence
• Call and Response: A Time-Resolved Study of Chromospheric Evaporation in a Large Solar Flare
• Dynamics in the transition region beneath active region upflows viewed by IRIS
• Electron density of active region outflows measured by the EUV Imaging Spectrometer onboard Hinode
• Transverse waves in coronal flux tubes with thick boundaries: The effect of longitudinal flows
• Formation and Dynamics of Transequatorial Loops
• Active region upflows: 1. Multi-instrument observations
• Signature and escape of highly fractionated plasma in an active region
• Solar Atmospheric Magnetic Energy Coupling: Broad Plasma Conditions and Spectrum Regimes
• Pre-flare and active region plasma flows and structure seen by the short wavelength camera on SOLAR-C/EUVST
• Line Profile Studies of Coronal Active Regions in Fe XII λ195.12 Using Hinode/EIS
• Active region upflows in various coronal structures and their coupling to the lower atmosphere
• Magnetic structure of coronal dark halos