First Results From SPICE EUV Spectrometer on Solar Orbiter

<p>SPICE (Spectral Imaging of Coronal Environment) is an EUV imaging spectrometer onboard Solar Orbiter. SPICE observes the Sun in two wavelength bands: 69.6-79.4 nm and 96.6-105.1 nm and is capable of recording full spectra in these bands with exposures as short as 1s. SPICE can measure spectra from the disk and low corona, and records all spectral lines simultaneously, using one of three narrow slits: 2”x11’, 4’’x11’, 6’’x11’, or a wide slit 30’’x14’. The primary mirror can be scanned in a direction perpendicular to the slit, allowing raster images of up to 16’ in size.</p><p>The first SPICE data were taken during the instrument commissioning carried out by the RAL Space team between 2020 April 21 and 2020 June 14, and at the first Solar Orbiter perihelion at 0.52AU between June 16-21.  We give examples of full spectra from the quiet Sun near disk centre and provide a list of key spectral lines from neutral hydrogen and ions of carbon, oxygen, nitrogen, neon, sulphur and magnesium. These lines cover the temperature range between 10,000 K and 1 million K (10MK in flares), providing slices of the Sun’s atmosphere in narrow temperature intervals. We show examples of raster images in several strong lines, obtained with different slits and a range of exposure times between 5s and 180s.</p><p>We have found several unusually bright, compact structures (named “beacons”) in the quiet Sun network, with extreme intensities up to 22 times greater than the average intensity across the image. The lifetimes of these sources are longer than 1 hour. We will derive plasma velocities in the beacon area, and co-align the SPICE rasters with the SDO/AIA 304 and 171 images and the HMI magnetic field to better understand the origin and properties of beacons.</p><p>We also show the first above-limb measurements with SPICE in Mg IX, Ne VIII and O VI lines, as obtained when the spacecraft pointed at the limb. Maps of Mg/Ne abundance ratios on disk can be derived and compared with in situ measurements to help confirm the magnetic connection between the spacecraft location and the Sun’s surface, and locate the sources of the solar wind.</p>

Effect of Slit Channel Width of a Shim Embedded in Slot-Die Head on High-Density Stripe Coating for OLEDs

With an attempt to achieve high-density fine organic stripes for potential applications in solution-processable organic light-emitting diodes (OLEDs), we have performed slot-die coatings using a shim with slit channels in various shapes (rectangular-shaped narrow, rectangular-shaped wide, and reversely tapered channels) in the presence of narrow µ-tips. Based on hydraulic-electric circuit analogy, we have analyzed the fluid dynamics of an aqueous poly (3,4-ethylenedioxythiophene): poly (4-styrenesulfonate) (PEDOT:PSS). It is observed that the coating speed can be increased and the stripe width can be reduced using a shim with rectangular-shaped wide slit channels. It is attributed that the hydraulic resistance is decreased and thus more fluid can reach a substrate through µ-tips. This behavior is consistent with the simulation result of the equivalent electrical circuit with a DC voltage source representing a pressure source. Using the shim with 150-µm-wide slit channels, we have successfully fabricated 200 PEDOT:PSS stripes within the effective coating width (150 mm) and 160 OLED stripes (34 stripes per inch) with the luminance of 325 cd/m2 at 5 V.

Experimental Study on Combined Cooling Method for Porous Struts in Supersonic Flow

A combined transpiration and opposing jet cooling method was experimentally investigated for protecting porous struts with microslits in the leading edge. Schlieren images showed that this cooling method significantly affects the stability of the flow field and the profile of the detached shock wave. Three different states of flow fields were observed when increasing the coolant injection pressure of a strut having a 0.20 mm wide microslit. The detached bow shock was pushed away by the opposing jet; it then became unstable and even disappeared when the coolant injection pressure was increased. Combined transpiration and opposing jet cooling could effectively cool the entire strut, especially the leading edge. The leading edge cooling efficiency increased from 3.5% for the leading edge without a slit to 52.8% for the leading edge with a 0.20 mm wide slit when the coolant injection pressure was 0.55 MPa. Moreover, combined transpiration and opposing jet cooling with nonuniform injection distribution made the strut temperature distribution more uniform and caused the maximum temperature to decrease compared to standard transpiration cooling.

A High-Throughput Imaging Spectrometer Based on Over-Scanning

We present a novel high-throughput imaging spectrometer based on over-scanning. The traditional slit-based spectrometer cannot gather enough radiation while the source is too weak. A much wider slit is used to replace the narrow one in traditional spectrometer. Too much wide slit will cause overlapping between different wavelength lights. In order to reconstruct super-resolution spectrum of source, over-scanning is employed which is realized by high precision electromechanical device. Experiments show that the reconstructed spectrum achieved a much higher resolution than original data meanwhile the throughput has improved significantly.