Chromospheric alfvenic waves strong enough to power the solar wind.

Alfvén waves have been invoked as a possible mechanism for the heating of the Sun's outer atmosphere, or corona, to millions of degrees and for the acceleration of the solar wind to hundreds of kilometers per second. However, Alfvén waves of sufficient strength have not been unambiguously observed in the solar atmosphere. We used images of high temporal and spatial resolution obtained with the Solar Optical Telescope onboard the Japanese Hinode satellite to reveal that the chromosphere, the region sandwiched between the solar surface and the corona, is permeated by Alfvén waves with strong amplitudes on the order of 10 to 25 kilometers per second and periods of 100 to 500 seconds. Estimates of the energy flux carried by these waves and comparisons with advanced radiative magnetohydrodynamic simulations indicate that such Alfvén waves are energetic enough to accelerate the solar wind and possibly to heat the quiet corona.

Coronal transverse magnetohydrodynamic waves in a solar prominence.

Solar prominences are cool 10(4) kelvin plasma clouds supported in the surrounding 10(6) kelvin coronal plasma by as-yet-undetermined mechanisms. Observations from Hinode show fine-scale threadlike structures oscillating in the plane of the sky with periods of several minutes. We suggest that these represent Alfvén waves propagating on coronal magnetic field lines and that these may play a role in heating the corona.

Evidence for Alfvén waves in solar x-ray jets.

Coronal magnetic fields are dynamic, and field lines may misalign, reassemble, and release energy by means of magnetic reconnection. Giant releases may generate solar flares and coronal mass ejections and, on a smaller scale, produce x-ray jets. Hinode observations of polar coronal holes reveal that x-ray jets have two distinct velocities: one near the Alfvén speed ( approximately 800 kilometers per second) and another near the sound speed (200 kilometers per second). Many more jets were seen than have been reported previously; we detected an average of 10 events per hour up to these speeds, whereas previous observations documented only a handful per day with lower average speeds of 200 kilometers per second. The x-ray jets are about 2 x 10(3) to 2 x 10(4) kilometers wide and 1 x 10(5) kilometers long and last from 100 to 2500 seconds. The large number of events, coupled with the high velocities of the apparent outflows, indicates that the jets may contribute to the high-speed solar wind.

Small-scale jetlike features in penumbral chromospheres.

We observed fine-scale jetlike features, referred to as penumbral microjets, in chromospheres of sunspot penumbrae. The microjets were identified in image sequences of a sunspot taken through a Ca II H-line filter on the Solar Optical Telescope on board the Japanese solar physics satellite Hinode. The microjets' small width of 400 kilometers and short duration of less than 1 minute make them difficult to identify in existing observations. The microjets are possibly caused by magnetic reconnection in the complex magnetic configuration in penumbrae and have the potential to heat the corona above a sunspot.

Twisting motions of sunspot penumbral filaments.

The penumbra of a sunspot is composed of numerous thin, radially extended, bright and dark filaments carrying outward gas flows (the Evershed flow). Using high-resolution images obtained by the Solar Optical Telescope aboard the solar physics satellite Hinode, we discovered a number of penumbral bright filaments revealing twisting motions about their axes. These twisting motions are observed only in penumbrae located in the direction perpendicular to the symmetry line connecting the sunspot center and the solar disk center, and the direction of the twist (that is, lateral motions of intensity fluctuation across filaments) is always from limb side to disk-center side. Thus, the twisting feature is not an actual twist or turn of filaments but a manifestation of dynamics of penumbral filaments with three-dimensional radiative transfer effects.

Narrow-bandpass multilayer mirrors for an extreme-ultraviolet Doppler telescope.

We have developed narrow-bandpass MoSi/Si multilayer mirrors for a Japanese sounding-rocket program. A high spectral resolution lambda/Deltalambda exceeding 40 was achieved by a two-mirror telescope with a multilayer coating. The single telescope had two bandpasses in the extreme-UV range for detecting a coronal high-velocity flow; the wavelength at peak reflectance (hereafter peak wavelength) in one of the bandpasses was 210.2 A, situated on the blue side of the target's Fe XIV 211.3-A coronal emission line, and the peak wavelength in the other was 213.3 A on the red side. A high uniformity in a peak wavelength of less than 1 A was achieved over a primary (secondary) mirror surface 158 (96) mm in diameter. The ratio of the reflectance for the Fe XIV line at 211 A to that for an intense He II line as a contaminant at 304 A in the telescope system became 2 x 10(5) owing to a wave trap consisting of a single Si layer on the MoSi/Si multilayer. The narrow-bandpass (approximately 5-A) telescope was launched on 31 January 1998 by sounding rocket S520CN-22, and images of the whole-Sun corona at Fe XIV 211 A were successfully obtained.

Purification and some characteristics of phosphatase of a psychrophile.

The phosphatase of a psychrophile was purified by ammonium sulfate fractionation, and a sequence of chromatographies on DEAE-Cellulofine, butyl-Cellulofine, Sephacryl S-100, and Mono-Q columns. The purified enzyme preparation was found to be electrophoretically homogeneous on native- and SDS-PAGE, and its molecular mass was determined to be 38.4 kDa by MALDI-TOF mass spectrometry. Maximal activity was observed at 30 degrees C and pH 6.0. Furthermore, the activity of this enzyme at 0 and 5 degrees C was 27 and 28%, respectively, of that at 30 degrees C. The enzyme was stable in the pH range of 6.0 to 8.0 and up to 20 degrees C. The enzyme was affected by metal ions; the activity was enhanced by Mg2+ and Ca2+ ions, but depressed by Zn2+ ions. Analysis of the amino acid composition indicated that this phosphatase contains no S-S bond, and only a few prolyl residues necessary to retain the rigid structure of a protein molecule. The phosphatase shows typical features of a cold enzyme; high catalytic activity at low temperature and rapid inactivation at an intermediate temperature.

Characteristics of Psychrophilic Alkaline Phosphatase.

The phosphatase of a psychrophile (Shewanella sp.) was purified by ammonium sulfate fractionation, followed by sequential column chromatographies. The purified enzyme was electrophoretically homogeneous on native- and SDS-PAGE. Its molecular weight was 41,826 by its amino acid composition. The enzyme had its optimal pH for the activity at 9.8, and a broad substrate specificity to dephosphorylate ATP, pyrophosphate, glycerophosphate, and so on. Its activity was increased by metal ions including Mg(2+), Mn(2+), and Co(2+). The maximal activity was observed at 40°C, and the enzyme at 0°C showed 39% of activity at 40°C. The enzyme, however, tended to lose its activity at 20°C and pH 9.8. These results indicated that purified enzyme was an alkaline phosphatase with characteristics; high catalytic efficiency at low temperature and gradual inactivation at an intermediate temperature.

High-wavelength-resolution extreme-ultraviolet multilayer mirror.

Multilayer mirrors with a system wavelength resolution (lambda/Dlambda) as high as 30-50 are required for the diagnostics of cosmic plasmas with temperatures of 1-20 MK. Such a high wavelength resolution can be realized by increasing the number of layer pairs contributing to the reflectance, by selecting less-absorbing materials for both the reflector and the spacer, and by decreasing the thickness of the reflector. We have fabricated a multilayer mirror tuned to 284 A with a silicon carbide reflector (20% thickness of the layer period) and an aluminum spacer and achieved lambda/Dlambda ~26.8 with a peak reflectivity of ~13.0%. This wavelength resolution is close to the value obtained with a numerical simulation and is considerably higher than the value obtained with the conventional Mo/Si multilayer.

The yohkoh mission for high-energy solar physics.

The Japanese Yohkoh satellite is now in orbit observing the sun with a set of x-ray imagers and x-ray and gamma-ray spectrometers. The data from this successful mission provide new information on solar flares and the sun's corona. This paper discusses the Yohkoh observations and presents a sample of the first scientific results from the mission.