Engineering topics

McKenzie, D. E.

Publications and source records attributed to McKenzie, D. E..

4 records

NASA NTRS2019

Lyman-Alpha Imaging Polarimetry with the CLASP2 Sounding Rocket Mission

Ultraviolet polarimetry offers a unique opportunity to explore the upper solar chromosphere and the transition region (TR) to the million-degree corona. These outer atmospheric regions play a key role in the transfer of mass and energy from the solar photosphere to the corona. With a sounding rocket experiment called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), in September 2015 we succeeded in obtaining the first measurement of the linear polarization produced by scattering processes in the hydrogen Lyman-alpha line of the solar disk radiation. The analysis and interpretation of such spectro-polarimetric observation allowed us to obtain information on the geometrical complexity of the corrugated surface that delineates the TR, as well as on the magnetic field strength via the Hanle effect. At the same time, the CLASP slit-jaw (SJ) optics system, which is a Lyman-alpha filter imager characterized by a FWHM (Full Width Half Maximum) equals 7 nanometers, allowed us to obtain broad-band Stokes-I and Q/I images over a large field of view. The obtained broad-band Q/I images are dominated by the scattering polarization signals of the Lyman-alpha wings, and not by the much weaker line-center signals where the Hanle effect operates. On April 11, 2019, we performed another sounding rocket experiment, called the Chromospheric LAyer Spectro-Polarimeter (CLASP2). We used the same instrument after significant modifications in order to obtain spectro-polarimetric observations of a plage and a quiet region in the Mg II h & k lines. At the same time, the CLASP2 SJ optics system allowed us to obtain broad-band Q/I and U/I images around the Lyman-alpha wavelength, in addition to the well- known SJ intensity images.

Kano, Ryouhei↗

NASA NTRS2017

CLASP2: The Chromospheric LAyer Spectro-Polarimeter

A major remaining challenge for heliophysicsis to decipher the magnetic structure of the chromosphere, due to its 'large role in defining how energy is transported into the corona and solar wind' (NASA's Heliophysics Roadmap). Recent observational advances enabled by the Interface Region Imaging Spectrometer (IRIS) have revolutionized our view of the critical role this highly dynamic interface between the photosphere and corona plays in energizing and structuring the outer solar atmosphere. Despite these advances, a major impediment to better understanding the solar atmosphere is our lack of empirical knowledge regarding the direction and strength of the magnetic field in the upper chromosphere. Such measurements are crucial to address several major unresolved issues in solar physics: for example, to constrain the energy flux carried by the Alfven waves propagating through the chromosphere (De Pontieuet al., 2014), and to determine the height at which the plasma β = 1 transition occurs, which has important consequences for the braiding of magnetic fields (Cirtainet al., 2013; Guerreiroet al., 2014), for propagation and mode conversion of waves (Tian et al., 2014a; Straus et al., 2008) and for non-linear force-free extrapolation methods that are key to determining what drives instabilities such as flares or coronal mass ejections (e.g., De Rosa et al., 2009). The most reliable method used to determine the solar magnetic field vector is the observation and interpretation of polarization signals in spectral lines, associated with the Zeeman and Hanle effects. Magnetically sensitive ultraviolet spectral lines formed in the upper chromosphere and transition region provide a powerful tool with which to probe this key boundary region (e.g., Trujillo Bueno, 2014). Probing the magnetic nature of the chromosphere requires measurement of the Stokes I, Q, U and V profiles of the relevant spectral lines (of which Q, U and V encode the magnetic field information).

Solar; Chromosphere; Polarization↗

NASA NTRS2013

The Solar Dynamics Observatory (SDO) Education and Outreach (E/PO) Program: Changing Perceptions One Program at a Time

We outline the context and overall philosophy for the combined Solar Dynamics Observatory (SDO) Education and Public Outreach (E/PO) program, present a brief overview of all SDO E/PO programs along with more detailed highlights of a few key programs, followed by a review of our results to date, conclude a summary of the successes, failures, and lessons learned, which future missions can use as a guide, while incorporating their own content to enhance the public's knowledge and appreciation of science and technology as well as its benefit to society.

STEM↗

NASA NTRS2011

The SDO Education and Outreach (E/PO) Program: Changing Perceptions One Program at a Time

The Solar Dynamics Observatory (SDO) Education and Public Outreach (E/PO) program began as a series of discrete efforts implemented by each of the instrument teams and has evolved into a well-rounded program with a full suite of national and international programs. The SDO E/PO team has put forth much effort in the past few years to increase our cohesiveness by adopting common goals and increasing the amount of overlap between our programs. In this paper, we outline the context and overall philosophy for our combined programs, present a brief overview of all SDO E/PO programs along with more detailed highlight of a few key programs, followed by a review of our results up to date. Concluding is a summary of the successes, failures, and lessons learned that future missions can use as a guide, while further incorporating their own content to enhance the public's knowledge and appreciation of NASA?s science and technology as well as its benefit to society.

Drobnes, E.↗