Plasma stealth: Difference between revisions

'''Plasma stealth''' is a proposed process to use ionized gas ([[plasma (physics)|plasma]]) to reduce the [[radar cross-section]] (RCS) of an [[aircraft]]. Interactions between [[electromagnetic radiation]] and ionized gas have been extensively studied for many purposes, including concealing aircraft from radar as [[stealth technology]]. Various methods might plausibly be able to form a layer or cloud of plasma around a [[vehicle]] to deflect or absorb radar, from simpler electrostatic or [[radio frequency]] (RF) discharges to more complex laser discharges.<ref name="laserplasma">{{cite conference

| issue=5 }}{{Failed verification|date=September 2014|reason=bibcode and doi do not point to the article named}}</ref> considers the use of a plasma panel for boundary layer control on a wing in a low-speed [[wind tunnel]]. This demonstrates that it is possible to produce a plasma on the skin of an aircraft. Radioactive Xenon [[nuclear poison]] or Polonium isotopes when successfully suspended in generated plasma layers or doped into vehicle hulls, may be utilized in order for a reduction in radar cross-section by generating a plasma layer on the surface.<ref name=Isotope>{{cite web|last1=August|first1=Henry|title=Energy Absorption by a Radioisotope Produced Plasma|url=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=12&f=G&l=50&co1=AND&d=PALL&s1=3713157&OS=3713157&RS=3713157|website=USPTO 3,713,157|date=January 23, 1973}}</ref> If tunable this could shield against HMP/EMP and HERF weaponry or act as optical radiation pressure actuators.{{clarify|what are these jargon abbreviations and what do they mean?}}

Boeing filed a series of patents related to the concept of plasma stealth. In US 7,744,039 B2, Jun. 2010, a system to control air flow with electrical pulses is described. In US 7,988,101 B2, Aug. 2011, a plasma generating device is used to create a plasma flow on the trailing edge, which can change its RCS. In US 8,016,246 B2 Sep. 2011, a plasma actuator system is used to camouflage weapon bay on a fighter when it is open. In US 8,016,247 B2, the plasma actuator system is described in detail, which is basically a dielectric barrier discharge (DBD) device. In US 8,157,528 B1 Apr. 2012, a plasma actuating cascade array for use on rotor blade is described. In US 8,220,753 B2 Jul. 2012, a system for controlling airflow on wing surface with pulsed discharge is described.

Control of plasma properties like density and temperature is important for a functioning plasma stealth device, and it may be necessary to dynamically adjust the plasma density, temperature, or combinations, or the magnetic field, in order to effectively defeat different types of radar systems. The great advantage Plasma Stealth possesses over traditional RFradio Stealthfrequency stealth techniques like shape morphing into [[LO geometry]]{{clarify|what is this?}} and use of [[radar-absorbent material]]s is that plasma is tunable and wideband. When faced with frequency hopping radar, it is possible, at least in principle, to change the plasma temperature and density to deal with the situation. The greatest challenge is to generate a large area or volume of plasma with good energy efficiency.

Plasma stealth technology also faces various technical problems. For example, the plasma itself emits EM radiation, fortunatelyalthough thisit is usually weak and noise-like in spectrum. Also, it takes some time for plasma to be re-absorbed by the atmosphere and a trail of ionized air would be created behind the moving aircraft, but at present there is no method to detect this kind of plasma trail at long distance. Thirdly, plasmas (like glow discharges or fluorescent lights) tend to emit a visible glow: this is not compatible with overall low observability concept. However, present optical detection devices like FLIR has a shorter range than radar, so Plasma Stealth still has an operational range space. Last but not the least, it is extremely difficult to produce a radar-absorbent plasma around an entire aircraft traveling at high speed, the electrical power needed is tremedoustremendous. However, a substantial reduction of an aircraft's RCS may be still be achieved by generating radar-absorbent plasma around the most reflective surfaces of the aircraft, such as the turbojet engine fan blades, engine air intakes, vertical stabilizers, and airborne radar antenna.

There have been several computational studies on plasma-based radar cross section reduction technique using three-dimensional FDTDfinite-difference time-domain simulations. Chaudhury et al. studied the electromagnetic wave attenuation of an Epstein profile plasma using FDTDthis method.<ref name="3drcs">{{cite journal

|bibcode = 2009ITPS...37.2116C }}</ref> Chung studied the radar cross change of a metal cone when it is covered with plasma, a phenomenon that occurs during reentry into the atmosphere.<ref name=Chung2>{{cite journal|last1=Chung|first1=Shen Shou Max|title=FDTD Simulations on Radar Cross Sections of Metal Cone and Plasma Covered Metal Cone|journal=Vacuum|date=Feb 8, 2012|volume=86|issue=7|pages=970–984|doi=10.1016/j.vacuum.2011.08.016|url=http://www.sciencedirect.com/science/article/pii/S0042207X11003411|publisher=ELSEVIERElsevier|bibcode = 2012Vacuu..86..970M }}</ref> Chung simulated the radar cross section of a generic satellite, and also the radar cross section when it is covered with artificially generated plasma cones.<ref name=Chung3>{{cite journal|last1=Chung|first1=Shen Shou Max|title=Simulation on Change of Generic Satellite Radar Cross Section via Artificially Created Plasma Sprays|journal=Plasma Source Science and Technology|date=Mar 30, 2016|volume=25|pages=035004|doi=10.1088/0963-0252/25/3/035004|bibcode = 2016PSST...25c5004C }}</ref>