28 research outputs found
New Results From Hinode: A Systems Science Approach To Heliophysics
Recent results from the analysis of Hinode data have been used to determine the origins of the fast and slow solar wind, possible heating sources for the solar corona, and onset locations for CMEs and polar x-ray jets. Using this information, and data collected by other observatories, major advances in the understanding of Heliophysics are now possible. These Hinode observations, and the techniques for analysis of the Hinode data will be discussed.
Observations of Transient Active Region Heating with Hinode
We present observations of transient active region heating events observed
with the Extreme Ultraviolet Imaging Spectrometer (EIS) and X-ray Telescope
(XRT) on Hinode. This initial investigation focuses on NOAA active region 10940
as observed by Hinode on February 1, 2007 between 12 and 19 UT. In these
observations we find numerous examples of transient heating events within the
active region. The high spatial resolution and broad temperature coverage of
these instruments allows us to track the evolution of coronal plasma. The
evolution of the emission observed with XRT and EIS during these events is
generally consistent with loops that have been heated and are cooling. We have
analyzed the most energetic heating event observed during this period, a small
GOES B-class flare, in some detail and present some of the spectral signatures
of the event, such as relative Doppler shifts at one of the loop footpoints and
enhanced line widths during the rise phase of the event. While the analysis of
these transient events has the potential to yield insights into the coronal
heating mechanism, these observations do not rule out the possibility that
there is a strong steady heating level in the active region. Detailed
statistical analysis will be required to address this question definitively
Marshall Space Flight Center SWG Meeting, Motivation for HCI/Solar-C
No abstract availabl
The Foggy EUV Corona and Coronal Heating by MHD Waves from Explosive Reconnection Events
In 0.5 arcsec/pixel TRACE coronal EUV images, the corona rooted in active regions that are at the limb and are not flaring is seen to consist of (1) a complex array of discrete loops and plumes embedded in (2) a diffuse ambient component that shows no fine structure and gradually fades with height. For each of two not-flaring active regions, found that the diffuse component is (1) approximately isothermal and hydrostatic and (2) emits well over half of the total EUV luminosity of the active-region corona. Here, from a TRACE Fe XII coronal image of another not-flaring active region, the large sunspot active region AR 10652 when it was at the west limb on 30 July 2004, we separate the diffuse component from the discrete loop component by spatial filtering, and find that the diffuse component has about 60% of the total luminosity. If under much higher spatial resolution than that of TRACE (e. g., the 0.1 arcsec/pixel resolution of the Hi-C sounding-rocket experiment proposed by J. W. Cirtain et al), most of the diffuse component remains diffuse rather being resolved into very narrow loops and plumes, this will raise the possibility that the EUV corona in active regions consists of two basically different but comparably luminous components: one being the set of discrete bright loops and plumes and the other being a truly diffuse component filling the space between the discrete loops and plumes. This dichotomy would imply that there are two different but comparably powerful coronal heating mechanisms operating in active regions, one for the distinct loops and plumes and another for the diffuse component. We present a scenario in which (1) each discrete bright loop or plume is a flux tube that was recently reconnected in a burst of reconnection, and (2) the diffuse component is heated by MHD waves that are generated by these reconnection events and by other fine-scale explosive reconnection events, most of which occur in and below the base of the corona where they are seen as UV explosive events, EUV blinkers, and type II spicules. These MHD waves propagate across field lines and dissipate, heating the plasma in the field between the bright loops and plumes
Blowout Jets: Hinode X-Ray Jets that Don't Fit the Standard Model
Nearly half of all H-alpha macrospicules in polar coronal holes appear to be miniature filament eruptions. This suggests that there is a large class of X-ray jets in which the jet-base magnetic arcade undergoes a blowout eruption as in a CME, instead of remaining static as in most solar X-ray jets, the standard jets that fit the model advocated by Shibata. Along with a cartoon depicting the standard model, we present a cartoon depicting the signatures expected of blowout jets in coronal X-ray images. From Hinode/XRT movies and STEREO/EUVI snapshots in polar coronal holes, we present examples of (1) X-ray jets that fit the standard model, and (2) X-ray jets that do not fit the standard model but do have features appropriate for blowout jets. These features are (1) a flare arcade inside the jet-base arcade in addition to the small flare arcade (bright point) outside that standard jets have, (2) a filament of cool (T is approximately 80,000K) plasma that erupts from the core of the jetbase arcade, and (3) an extra jet strand that should not be made by the reconnection for standard jets but could be made by reconnection between the ambient unipolar open field and the opposite-polarity leg of the filament-carrying flux-rope core field of the erupting jet-base arcade. We therefore infer that these non-standard jets are blowout jets, jets made by miniature versions of the sheared-core-arcade eruptions that make CME
Testing the Solar Probe Cup, an Instrument Designed to Touch the Sun
Solar Probe Plus will be the first, fastest, and closest mission to the sun, providing the first direct sampling of the sub-Alfvenic corona. The Solar Probe Cup (SPC) is a unique re-imagining of the traditional Faraday Cup design and materials for immersion in this high temperature environment. Sending an instrument of this type into a never-seen particle environment requires extensive characterization prior to launch to establish sufficient measurement accuracy and instrument response. To reach this end, a slew of tests for allowing SPC to see ranges of appropriate ions and electrons, as well as a facility that reproduces solar photon spectra and fluxes for this mission. Having already tested the SPC at flight like temperatures with no significant modification of the noise floor, we recently completed a round of particle testing to see if the deviations in Faraday Cup design fundamentally change the operation of the instrument. Results and implications from these tests will be presented, as well as performance comparisons to cousin instruments such as those on the WIND spacecraft
Loop Evolution Observed with AIA and Hi-C
In the past decade, the evolution of EUV loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this presentation we discuss the first results of loop analysis comparing AIA and Hi-C data. In the past decade, the evolution of EUV loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this presentation we discuss the first results of loop analysis comparing AIA and Hi-C data