Abstract: A charged particle induction apparatus and method comprising a high power light emitting means, such as a laser array, in operable communication with a high energy output means to accomplish initiation of at least two concentric plasma channels in atmosphere extending from the Earth's surface to the charge-rich upper atmosphere, including the ionosphere, for the transmission of charged particles therethrough to ground using the surrounding atmosphere as an insulator. The transmitted energy is drawn down (due to an artificially created potential) through the conductive plasma channels to collection means.

Abstract: Self-balancing, corona discharge for the stable production of electrically balanced and ultra-clean ionized gas streams is disclosed. This result is achieved by promoting the electronic conversion of free electrons into negative ions without adding oxygen or another electronegative gas to the gas stream. The invention may be used with electronegative and/or electropositive or noble gas streams and may include the use of a closed loop corona discharge control system.

Abstract: An ion generator 10a has an ejection head 18 as an opposite electrode and a discharge electrode 16, and generates air ions by corona discharge. A nozzle 14 supporting the discharge electrode 16 is attached to a base member 12 formed with an air supply path 11, and the nozzle 14 is formed with an exposure surface 24 for exposing the tip end portion 16b of the discharge electrode 16 and a tapered surface 25. The nozzle 14 is formed with air guide holes 26 which communicate with the air supply path 11, and ejection ports of the air guide holes 26 are open on the tapered surface 25. Compressed air ejected from the ejection port is flowed along the tapered surface 25 so that outside air surrounding the nozzle 14 is involved in the compressed air, and sprayed in a front direction of the discharge electrode 16.

Abstract: A sterilizing apparatus and an ion generating apparatus, which generate sufficient amount of cations in a short period of time and also maintain the amount of ions generated at a level that is harmless to the human body. The sterilizing apparatus and the ion generating apparatus optimize the position of an electrode to maximize the generation of active hydrogen. The ion generating apparatus includes a first electrode for generating hydrogen ions and a second electrode located such that the second electrode is separated from the first electrode by a designated distance for generating electrons and superoxide anions. The hydrogen ions generated from the first electrode react with the electrons generated from the second electrode to produce hydrogen atoms, and the hydrogen atoms react with the superoxide anions generated from the second electrode to sterilize the air.

Abstract: The present invention provides methods and systems for an ion generator mounting device for application of bipolar ionization to airflow within a conduit, the device includes a housing for mounting to the conduit having an internal panel within the enclosure, and an arm extending from the housing for extension into the conduit and containing at least one opening. At least one coupling for mounting an ion generator to the arm oriented with an axis extending between a pair of electrodes of the ion generator being generally perpendicular to a flow direction of the airflow within the conduit.

Abstract: A bipolar charger includes a housing with a main chamber and positive and negative electrode chambers facing each other. The electrode chambers each have a ground electrode and a high voltage electrode that cooperate to create a cloud of ions. An aerosol flowing from an inlet passage through the main chamber and out an outlet passage mixes with the clouds of ions, thereby providing an aerosol with a steady-state electric charge distribution.

Abstract: A method and a device for automatic positive and negative ion balance control in a bipolar ion generator. The method may include applying bias voltage from a bias voltage source to a bias electrode from a power supply that includes an AC voltage generator and a voltage multiplying circuit of at least one cascade. The method may also include controlling a bias current flowing through the bias electrode for the purpose of stabilization of that current, wherein the step of controlling of the bias current is performed during charging of a capacitor in the voltage multiplying circuit.

Abstract: A discharge device includes a dielectric, a first electrode and a second electrode arranged with the dielectric interposed therebetween, and a circuit unit to which the first electrode and the second electrode are electrically connected for generating a high voltage to be applied to the first electrode and to the second electrode. The dielectric is formed in a tube shape or a pipe shape having therein the circuit unit.

Abstract: A low maintenance AC gas-flow driven static neutralizer, comprising at least one emitter and at least one reference electrode; a power supply having an output electrically coupled to the emitter(s) and a reference terminal electrically coupled to the reference electrode(s) with the power supply disposed to produce an output waveform that creates ions by corona discharge and to produce an electrical field when this output waveform is applied to the emitter(s); a gas flow source disposed to produce a gas flow across a first region that includes these generated ions and the emitter(s), the gas flow including a flow velocity; and wherein, during a first time duration, the output waveform decreases an electrical force created by the electrical field, enabling the gas flow to carry away from the emitter(s) a contamination particle that may be located within a second region surrounding the emitter(s), and to minimize a likelihood of the contamination particle from accumulating on the emitter(s).

Abstract: Provided is a static eliminator capable of holding ion balance uniform regardless of a distance from the static eliminator. The static eliminator includes: an electrode driving device that alternately and repeatedly applies, to a discharge electrode, a positive drive voltage and a negative drive voltage as drive voltages for corona discharge; decreases a ratio of the application time of the positive drive voltage while relatively increasing the voltage value of the positive drive voltage in a case of increasing positive ions, and increases the ratio of the application time of the positive drive voltage while relatively decreasing the voltage value of the positive drive voltage in a case of increasing negative ions.

Abstract: A system and method of treating air. Bipolar ionization is delivered to an airflow within a conduit from a tubeless ion generator. The ionized airflow may be delivered to a conditioned airspace by an HVAC system. In alternate applications, the airflow delivers ionized combustion air to an engine. The invention also includes a mounting assembly for positioning one or more ion generators into an airflow.

Abstract: In one example, this disclosure describes a circuit and techniques that may be used to measure the ion balance in an ionization balance device (10). The described circuit comprises a capacitor (22) that includes two conductors (23, 24), wherein a first one (23) of the conductors is exposed to the output of the ionization device, and the second one (24) of the conductors is shielded from the output of the ionization device. The first conductor may accumulate charge so as to quantify the output of the ionization balance device. A switch (29) may be used to discharge the first conductor at periodic intervals in order to measure the accumulated charge on the first conductor, and signal processing may be performed on this discharge measurement in order to generate feedback that can be used to control and adjust the output of an ion source.

Abstract: A method for the neutralization of aerosol particles uses a bipolar ion atmosphere generated by a dielectric barrier discharge to achieve a symmetric charge distribution on the particles. The aerosol-laden sample air passes, with a defined velocity, through the central flow channel of a first electrode, an adjoining discharge chamber and a downstream equilibration chamber. The wall electrode and the discharge chamber are surrounded by a plasma-resistant dielectric. The dielectric is at least in the region of the discharge chamber surrounded by a ring-shaped excitation electrode. A pulsating high voltage applied to the excitation electrode causes a dielectric barrier discharge between wall electrode and dielectric in the largely field-free discharge chamber, which generates positive and negative ions. A rod-shaped control electrode generates a weak electric field.

Abstract: An ionizer that acts as an electric charge generating device includes a first high voltage power source and a second high voltage power source, which are disposed in confronting relation to each other, and a first wiring arrangement and a second wiring arrangement, which are disposed in confronting relation to each other. The first high voltage power source applies an AC high voltage to needle electrodes via the first wiring arrangement, whereas the second high voltage power source applies an AC high voltage, which is 180° out of phase with the aforementioned AC high voltage, to needle electrodes via the second wiring arrangement.

Abstract: A shock wave in a gas is modified by emitting energy to form an extended path in the gas; heating gas along the path to form a volume of heated gas expanding outwardly from the path; and directing a path. The volume of heated gas passes through the shock wave and modifies the shock wave. This eliminates or reduces a pressure difference between gas on opposite sides of the shock wave. Electromagnetic, microwaves and/or electric discharge can be used to heat the gas along the path. This application has uses in reducing the drag on a body passing through the gas, noise reduction, controlling amount of gas into a propulsion system, and steering a body through the gas. An apparatus is also disclosed.

Abstract: A duct frame includes: a first airflow path configured to include a first outlet; a second airflow path configured to include a second outlet disposed close to the first outlet; an ion generator configured to be provided in the second airflow path and to divide the second airflow path into a first divided flow path and a second divided flow path; and a minute flow path configured to provide under the ion generator and to have a flow path resistance higher than the flow path resistance of the first divided flow path of the second airflow path.

Abstract: Small form-factor ion flow fluid movers that provide electrostatically operative surfaces in a flow channel adjacent to an emitter electrode, but upstream of a collector electrode or electrodes, can shape operative electric fields and influence ion flows in ways that accentuate downstream flow while minimizing upstream ion migration. In some cases, dielectric surfaces (or even electrically isolated conductive surfaces) along a flow channel adjacent to an emitter electrode can be configured to collect and retain an initial population of generated ions and thereafter electrostatically repel further ions. Depending on the configuration of such dielectric or electrically isolated conductive surfaces, these repelling electrostatic forces may dissuade ion migration or flow from sensitive but closely proximate components and/or may shape fields to enhance ion flows in a desired downstream direction.

Abstract: A device collects electrostatic charge from the atmosphere and stores the electrostatic charge for further use. The device includes a primary array including a plurality of electrically-conducting collectors, a plurality of electrically-conducting inductors, a charge regulator, and a charge storage device. A secondary array can be added to improve the efficiency of the primary array.

Abstract: An air ionizer electrode assembly (10; 50; 60) comprising an inner electrode (11; 52; 66), at least one outer electrode (14, 15; 54; 61) and a dielectric barrier (12, 13; 53; 64) sandwiched between the inner electrode and the at least one outer electrode. The inner electrode has a continuous overall surface and the at least one outer electrode has a plurality of holes (21; 56; 70) to provide a plurality of ion generating points for generation of negative ions.

Abstract: A multi-sectional linear ionizing bar with at least four elements is disclosed. First, disclosed bars may include at least one ionization cell with at least one axis-defining linear ion emitter for establishing an ion cloud along the length thereof. Second, disclosed bars may include at least one reference electrode. Third, disclosed bars may include a manifold for receiving gas or air from a source and for delivering same past the linear emitter(s) such that substantially none of the gas/air flows into the ion cloud. Fourth, disclosed bars may include means for receiving the ionizing voltage and for delivering same to the linear emitter(s) to thereby establish the ion cloud. In this way, disclosed ionizing bars may transportions from the plasma region toward a charge neutralization target without inducing substantial vibration of the linear emitter and without substantial contaminants from the gas/air flow reaching the linear emitter.

Abstract: An indoor located air distribution device for providing distribution of purified supply air to a service area. The air distribution device with air purifier can reduce the amount of bacteria, viruses, and bad spores inside the service area, can minimize the spreading of bacteria, viruses and spores, and can create overall healthier conditions in the service area. With low energy usage and maintenance cost, an air supply unit with built-in bi-polar air purifier can improve the quality of room breathable air, minimize the amount of outside air in total supply air, and decrease the usage of energy (heating/cooling) and electricity.

Abstract: An electrohydrodynamic fluid accelerator apparatus includes a corona electrode having an axial shape and configured to receive a first voltage. The electrohydrodynamic fluid accelerator apparatus includes a collector electrode disposed coaxially around the at least one corona electrode and configured to receive a second voltage. Application of the first and second voltages on the corona electrode and the collector electrode, respectively, causes fluid proximate to the corona electrode to ionize and travel in a first direction between the corona electrode and the collector electrode, thereby causing other fluid molecules to travel in a second direction to generate a fluid stream. In at least one embodiment of the invention, the ionized fluid proximate to the emitter electrode travels in a radial direction from the corona electrode to the collector electrode, causing the other fluid molecules to travel in an axial direction to thereby generate the fluid stream.

Abstract: An electronic system is configurable to accommodate either of a mechanical air mover and an EHD air mover within an enclosure. At least one of a plurality of electronic components is selectively configurable to alternately accommodate the mechanical air mover or the EHD air mover within the enclosure. The mechanical fan or EHD is positioned to motivate air flow along a air flow path between inlet and outlet ventilation boundaries of the enclosure. A connector for a respective one of the electronic components allows for selective configuration in an alternate orientation of the respective one of the electronic components to accommodate a difference in geometry between the EHD air mover and the mechanical air mover.

Abstract: An ion airflow generating device includes a number of generator stages, each of which includes a number of generators. Each generator includes a needle-shaped emitter and a ring-shaped receiver. The receivers in the same stage are arranged in an array. Each receiver defines a groove in an outer circumferential surface thereof along a direction parallel to the central axis thereof. Each two adjacent receivers in a former generator stage connect with each other, and the grooves thereof cooperatively define a hole for holding an emitter in a next generator stage. The receivers in the next generator stage symmetrically offset from the receivers in the former generator stage such that each emitter aligns to the center of a corresponding receiver.

Abstract: A wind power negative ion generator includes a negative ion generator main body and a wind power generation device coupled to the negative ion generator main body. The wind power generation device has a power cord connected to a power line of the negative ion generator to supply electricity. The wind power generation device includes fan blades to communicate with outside and form a wind receiving side. The negative ion generator of the present invention can be widely used, not limited to a fixed power source socket. The negative ions generated by the present invention can move along with the wind to enlarge the range of the negative ions.

Abstract: In an ion generating unit configured to control driving of a plurality of ion generating elements for generating ions by a controller, the controller drives the ion generating elements upon start up, and is configured to keep driving for a predetermined time period; thereby, the ion concentration of a space upon start up is quickly raised to a predetermined concentration. Further, the controller is configured to drive the ion generating elements intermittently and one after another in order after the predetermined time period has elapsed; the product life is elongated while maintaining the predetermined ion concentration and shortening the driving time of the ion generating elements.

Abstract: Provided is an ion wind generator capable of suitably generating an ion wind along the surface of a dielectric. An ion wind generator has: a dielectric having a first primary surface and a second primary surface at the rear thereof; an inner side electrode arranged in the dielectric; a first electrode arranged on the first primary surface side with respect to the inner side electrode; and a second electrode arranged on the second primary surface side with respect to the inner side electrode. The inner side electrode has a first downstream area located in a first direction (the positive side of x-axis direction) along the first primary surface with respect to the first electrode, and a second downstream area located in a second direction (the positive side of x-axis direction) along the second primary surface with respect to the second electrode.

Abstract: Self-balancing, corona discharge for the stable production of electrically balanced and ultra-clean ionized gas streams is disclosed. This result is achieved by promoting the electronic conversion of free electrons into negative ions without adding oxygen or another electronegative gas to the gas stream. The invention may be used with electronegative and/or electropositive or noble gas streams and may include the use of a closed loop corona discharge control system.

Abstract: Provided is an ion wind generator which is able to raise the speed of the ion wind. An ion wind generator (3) has: a first electrode (9) and a second electrode (11) which are supplied with voltage and induce an ion wind by electric discharge, and a third electrode (13) which forms an electric field for accelerating the ion wind in a downstream region of the ion wind relative to the first electrode (9) and the second electrode (11).

Abstract: A method of processing acoustic waves emitted at an outlet of a turbo engine of an aircraft with a dielectric barrier discharge device, and an aircraft including such a device. The method includes activating the dielectric barrier discharge device so as to emit an electric wind in a direction of acoustic waves so as to attenuate the acoustic waves. An aircraft can include such a dielectric barrier discharge device.

Abstract: An ion/ozone wind generation device includes an electrode pair including a needle-shaped electrode and an opposite electrode, and generates ions and ion/ozone wind using corona discharge by generating a potential difference between the needle-shaped electrode and the opposite electrode, wherein the opposite electrode includes a plane-shaped main ring-shaped opposite electrode and a plane-shaped sub ring-shaped opposite electrode surrounding the plane-shaped main ring-shaped opposite electrode, and the longest distance between a tip of the needle-shaped electrode and the main ring-shaped opposite electrode is shorter than the shortest distance between the tip of the needle-shaped electrode and the sub ring-shaped opposite electrode.

Abstract: An ion generator to generate ion flow to ventilate heat comprises an emitter, a receiver and a power supply. The emitter comprises a needle electrode having one needle shaped tip configured as a discharging portion. The receiver comprises a plurality of flow channels for airflow and at least one receiving portion. The at least one receiving portion comprises a line edge arranged around a concave spherical surface, and the discharging portion is at a substantial center of the concave spherical surface. The power supply provides a voltage potential difference between the discharging portion of the emitter and the receiving portions of the receiver.

Abstract: A maintenance operation of an ion generator can be easily performed. A device main body has an inner case and an outer case, and the inner case having a support block and an air supply pipe is inserted into the outer case. An opposite electrode is detachably mounted in the support block from a front side of the device main body, and a discharge needle unit is detachably mounted from a reversed direction thereto. The discharge needle unit has a holder, in which the discharge electrode is provided, and a sleeve, which forms an ion generating space between the opposite electrode and the sleeve, is detachably mounted in the holder. Air supplied from an outside is supplied to the ion generating space via a flow path in the air supply pipe.

Abstract: An electrohydrodynamic (EHD) air mover is positionable within the enclosure to, when energized, motivate air flow through the enclosure along a flow path between the inlet and outlet ventilation boundaries. Ductwork within the enclosure has cross-sections substantially matched to a cross-section of the EHD air mover. A fan curve-type, pressure-air flow characteristic measured for the EHD air mover in open air substantially overstates mechanical impedance of the EHD air mover to air flow along the flow path between the inlet and outlet ventilation boundaries in that, when the EHD air mover is operably positioned within the enclosure appurtenant to the ductwork, no more than about 50% of the mechanical impedance of the EHD air mover indicated by the measured fan curve-type, pressure-air flow characteristic actually contributes to total mechanical impedance to air flow through the enclosure along the flow path between the inlet and outlet ventilation boundaries.

Abstract: A static eliminator comprises an electric discharge portion, and a case in which the discharge portion for emitting ions in front thereof is disposed. The case includes an ion emitting opening and an ozone, etc suction opening. The ozone, etc generated in the discharge portion is sucked through the ozone, etc suction opening resulting in sucking air from the ion emitting opening in a direction opposite to that of ion emission through the ion emitting opening.

Abstract: An ion/ozone wind generation device includes an electrode pair including a needle-shaped electrode and an opposite electrode, and generates ions and ion/ozone wind using corona discharge by generating a potential difference between the needle-shaped electrode and the opposite electrode, wherein the opposite electrode includes a plane-shaped main ring-shaped opposite electrode and a plane-shaped sub ring-shaped opposite electrode surrounding the plane-shaped main ring-shaped opposite electrode, and the longest distance between a tip of the needle-shaped electrode and the main ring-shaped opposite electrode is shorter than the shortest distance between the tip of the needle-shaped electrode and the sub ring-shaped opposite electrode.

Abstract: Embodiments provide various apparatus and techniques for deflecting or redirecting a flow of ionized air generated from an ionic wind generator. In general, a deflection field generator can be located proximate to the path of the flow of ionized air. The deflection field generator is configured to generate an electromagnetic field, which deflects a least a portion of the flow of ionized air to a different path and may possibly increase local heat transfer.

Abstract: Small form-factor ion flow fluid movers that provide electrostatically operative surfaces in a flow channel adjacent to an emitter electrode, but upstream of a collector electrode or electrodes, can shape operative electric fields and influence ion flows in ways that accentuate downstream flow while minimizing upstream ion migration. In some cases, dielectric surfaces (or even electrically isolated conductive surfaces) along a flow channel adjacent to an emitter electrode can be configured to collect and retain an initial population of generated ions and thereafter electrostatically repel further ions. Depending on the configuration of such dielectric or electrically isolated conductive surfaces, these repelling electrostatic forces may dissuade ion migration or flow from sensitive but closely proximate components and/or may shape fields to enhance ion flows in a desired downstream direction.

Abstract: A duct frame includes: a first airflow path configured to include a first outlet; a second airflow path configured to include a second outlet disposed close to the first outlet; an ion generator configured to be provided in the second airflow path and to divide the second airflow path into a first divided flow path and a second divided flow path; and a minute flow path configured to provide under the ion generator and to have a flow path resistance higher than the flow path resistance of the first divided flow path of the second airflow path.

Abstract: The present invention relates to a device and a method for communication, and a program that makes it possible to provide a communication environment not limited by a use environment. An electrode controlling unit 261 in a transmitting device 260 checks a state of capacitive coupling of each of an electrode 271 and an electrode 272 in an electrode unit 262 with surroundings, controls connection of each electrode to a transmitting unit 263 according to a result of the check, and makes the electrode 271 and the electrode 272 function as a transmission signal electrode or a transmission reference electrode, the transmission signal electrode and the transmission reference electrode being different from each other. The transmitting unit 263 connects the electrode 271 and the electrode 272 to an amplifying unit under control of the electrode controlling unit 261, and transmits a signal to a communication medium 280 via one of the electrodes. The present invention is applicable to communication systems.

Abstract: The present invention relates to a method of deactivating an antigenic substance by causing positive and negative ions to act on the antigenic substance, and the positive and negative ions are caused to act in an atmosphere in which each of positive ion concentration and negative ion concentration is at least about 50,000/cm3, and more preferably, at least about 100,000/cm3.

Abstract: A method for controlling an ionization device for ionizing air for the ventilation of motor vehicle interiors. The ionization device releases ions of a first ion type at least intermittently. In addition, the ionization device is operated at least intermittently in at least one regeneration mode.

Abstract: An ionic thermal dissipation device includes an ionic wind generation system and a power system. The power system first converts external direct current (DC) power signals into first alternating current (AC) power signals, and boosts, increases voltage, and rectifies the first AC power signals to generate high voltage DC power signals to drive the ionic wind generation system. The power system also detects current signals generated by ion excitation of the ionic wind generation system and voltage signals of the high voltage DC power signals, and regulates the high voltage DC power signals and time of driving the ionic wind generation system according to a first PWM signal and a first analog signal from an electronic device and the detected current signals and voltage signals.

Abstract: A static eliminator that can adjust the balance in the quantities of positive and negative ions reaching a charged object. A static eliminator (1) includes: a first electrode (5) which is disposed inside a housing (2) having at least one open end (2a) and is connected to a positive terminal of a power supply (3); a second electrode (4) which is disposed inside the housing (2) by being spaced a prescribed distance away from the first electrode (5) and is connected to a negative terminal of the power supply (3); and an air provider (6) for producing a stream of air by which the positive ions emitted from the first electrode (5) and the negative ions emitted from the second electrode (4) are delivered to a charged object. At least one of the first and second electrodes (4) and (5) is disposed in such a manner one electrode is linearly movable relative to the other electrode in at least one of forward and backward directions along a direction in which the stream of air flows.

Abstract: The present invention provides an air treatment apparatus. The air treatment apparatus comprises a housing electrically connectable to a voltage source and generating a high voltage and a glass tube. The air treatment apparatus further comprises a tube base electrically connecting internally high voltage to an inner electrode within the glass tube and electrically connected internally an outer electrode surrounding the glass tube and a tube socket electrically connected internally to the outer electrode and electrically connected to a grounding pad, wherein the grounding pad is mechanically connectable to the housing and electrically connectable to the housing.

Abstract: Techniques are described for integration of EHD-type air movers with electronic systems, and in particular, for limiting infiltration of ions and/or charged particulates into an internal air plenum. In some designs, it may be desirable to allow or even encourage EHD motivated air flow (whether drawn or forced) through the internal air plenum while providing a barrier to transit of ions and/or charged particulates that may be generated during EHD operation. Such a barrier may employ electrostatic forces to impede transit of ions and/or charged particulate across a vent positioned to allow air flow from or into the internal air plenum. In some cases, an electrostatic barrier may include a fluid permeable mesh or grill that spans a substantial cross-section of the vent.

Abstract: A computer enclosure includes a case, a system fan, and a negative ion generator. The case defines an air outlet. The system fan is arranged in the case adjacent to the air outlet. The negative ion generator is arranged in the case to generate negative ions. The generated negative ions spread in the case and are expelled from the case through the air outlet by airflow generated by the system fan.

Abstract: A space-saving mounting structure of an air blower having a vibration-insulating function is achieved to reduce a size of an ion generating apparatus. A holding case that holds an air blower and a mount having an air blowing duct are provided in a body case. A cushioning member is provided on an outer surface of a fan casing of the air blower. The air blower is held between the holding case mounted to the body case and the mount as a part of the body case. Two mounting members are formed on the fan casing. One mounting member is held between a pair of regulating members and formed on the holding case. The other mounting member is held between regulating members and formed on the holding case and the mount, respectively.

Abstract: Airflow in a computer chassis may be enhanced or reduced to affect cooling of heat generating devices using an ionic air moving device. A plurality of ionic air moving devices enhance or reduce airflow through a plurality of fluidically parallel airflow zones of the computer chassis in an airflow direction established by a nonionic air moving device. Each ionic air moving device comprises an ion emitter electrode disposed a spaced distance from a collector electrode, wherein a controller independently controls an electrical potential between the emitter and collector electrodes of each ionic air moving device for affecting the rate of airflow through one or more of the plurality of airflow zones.

Abstract: There is provided a static eliminator capable of weakening an electric field between a discharge electrode and a ground electrode, to generate a strong electric field between the discharge electrode and a workpiece, in which a first-stage circumferential chamber, a second-stage circumferential chamber and a first gas pool are arrayed in series along the longitudinal direction of a discharge electrode, the first gas pool is disposed in the mode of diametrically overlapping a gas outflow channel for shielding located on the inner circumferential side of the first gas pool, a gas is supplied to the first gas pool through the chambers disposed at multi-stages by means of the circumferentially spaced multi-stage orifices (the first and second chases), a ground electrode plate member in plate shape is buried in an insulating resin member on the bottom surface side of the half base in a position as high as where the first gas pool is located, and the ground electrode plate member includes a circular ring section con