Apr 19, 2021
Researchers use laser paintbrush to create miniature masterpieces
Posted by Quinn Sena in category: media & arts
Researchers are blurring the lines between science and art by showing how a laser can be used to create artistic masterpieces in a way that mirrors classical paints and brushes. The new technique not only creates paint-like strokes of color on metal but also offers a way to change or erase colors.
“We developed a way to use a laser to create localized color on a metallic canvas using a technique that heats the metal to the point where it evaporates,” said research team leader Vadim Veiko from ITMO University in Russia. “With this approach, an artist can create miniature art that conveys complex meaning not only through shape and color but also through various laser-induced microstructures on the surface.”
In Optica, The Optica l Society’s (OSA) journal, Veiko and colleagues show that their new laser tools can be used to create unique colorful paintings, including a miniature version of Van Gogh’s painting “The Starry Night.”
$S = L V_A/\eta$ (
$V_A$ is the Alfven velocity based on the poloidal reconnecting magnetic field, 
$L$ is the current sheet length and 
$\eta$ is the magnetic diffusivity) exceeds a critical value (typically a few thousand). Our thruster concept is based on the formation of this elongated current sheet for triggering fast reconnection and plasmoid formation. Effects beyond MHD may also contribute to fast reconnection as the current sheet width (
$\delta _{\mathrm {sp}}$) becomes smaller than the two-fluid or kinetic scales (Cassak, Shay & Drake 
$104$ and above), which is achieved at high magnetic field rather than low magnetic diffusivity (or high temperature). To form a single or multiple X-point reconnection site, oppositely directed biased magnetic field (in the range of 20–1000 G) is injected through a narrow gap in an annular device. We find that the plasmoid structures demonstrated in resistive (or extended) MHD simulations produce high exhaust velocity and thrust that scale favourably with applied magnetic field. It will be shown that the fluid-like magnetic plasmoid loops continuously depart the magnetic configuration about every 
$10 \ \mathrm {\mu } \textrm {s}$ with Alfvenic velocities in the range of 20 to 
$500\ \textrm {km}\ \textrm {s}^{-1}$, and the thrust does not ideally depend on the mass of the ion species of the plasma.
$B^{\mathrm {inj}}_P$, in blue, with radial, 
$R$, and vertical, 
$Z$, components), connecting the inner and outer biased plates in the injector region. Gas is injected and partially ionized by applying an injector voltage 
$V_{\mathrm {inj}}$ of a few hundred volts between the inner and outer plates (indicated by numbers 1 and 2), which also drives a current 
$I_{\mathrm {inj}}$ along the open magnetic field lines. Plasma and open field lines expand into the vessel when the Lorentz force 
$J_{\mathrm {pol}} \times B_{\phi }$ exceeds the field line tension of the injector poloidal field. The azimuthal (
$\phi$) field shown here, 
$B_{\phi }$, is generated through injector current (
$I_{\mathrm {inj}}$) alone (by applying 
$V_{\mathrm {inj}}$), or can be provided externally.
