US20080302514A1

US20080302514A1 - Plasma cooling heat sink

Info

Publication number: US20080302514A1
Application number: US12/157,233
Authority: US
Inventors: Chien Ouyang
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-06-09
Filing date: 2008-06-08
Publication date: 2008-12-11
Also published as: WO2008153988A1; TW200951391A

Abstract

One embodiment of the present invention uses plasma-driven gas flow to cool down electronic devices. The cooling device comprises heat sink fin assembly, plasma actuator assembly, and magnetic circuit assembly. The plasma actuator assembly comprises electrodes and dielectric pieces. Voltages are applied to electrodes to drive the plasma gas flow. The magnetic circuit assembly provides magnetic field to interact with electrical field and plasma flow, and therefore an induced gas flow is pumped into, or pumped out from, heat sink fin assembly, to cool down heat sink fins.

Description

This application is a Formal Application and claims priority to pending U.S. patent application 60/934,047 filed on Jun. 9, 2007 by the same Applicant of this Application, the benefit of its filing date being hereby claimed under Title 35 of the United States Code.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates generally to electronic equipment, and more particularly, to apparatus and methods for cooling electronic devices using plasma-driven gas flow.
2. Description of the Related Art
Electronic devices may generate significant heat during operation. High temperatures may reduce the lifespan of these devices, and, therefore, the generated heat may need to be dispersed to keep the operating temperature of the electronic devices within acceptable limits.
One commonly used cooling device is heat sink. Heat sinks may be coupled to electronic devices to absorb heat through the heat sink base and disperse the heat through their fins. Conventional methods to disperse the heat through the heat sink fins are natural convection and forced convection. Natural convection is to disperse the heat away from the surfaces of heat sink fins without the aid of external forced fluid pumping through heat sink fins. On the other hand, the forced convection cooling is to pump the fluid to flow through heat sink fins, such as the fans to blow the air through the heat sink fins, and therefore enhance the heat transfer between fins and outside ambient.
With the increasing power density of electronic devices, the pitch or the distance between heat sink fins is becoming smaller, which means more surface area may be used to transport the heat away. However, when the pitch becomes very small, the pressure drop between inlet and outlet of the heat sink fins may become very high, which may results the difficulties to pump the fluid flowing through fins, and as a result, more powerful fans, which consume higher electricity may be needed for the cooling. The invention utilizes plasma-driven gas flow to conduct the convective heat transfer along the heat sink fins and therefore will resolve these issues.
Another consideration of the electronic device cooling is that, due to size concern, the internal space allowed to put cooling fans and other cooling components, may be limited or not permitted. The invention utilizes the plasma-driven gas flow to generate the forced convective heat transfer on the heat sink fins, and hence, is able to improve the heat transfer efficiency and to minimize the required space because some cooling components are assembled inside heat sink fins.
Another aspect of using the invention is to lower the required power of the system fans of electronic devices. The plasma driven gas flow on the heat sink fins will induce the local turbulence on the heat sink surfaces. Higher momentum of the fluid is obtained and the cooling is achieved. Therefore, in this way, the system fan doesn't need to be very powerful in order to cool down heat source.
Plasma-driven gas flow has been used either to cool articles or to control and modify the fluid dynamics boundary layer on the wings surfaces of the aerodynamic vehicles. For example, U.S. Pat. No. 3,938,345 used the phenomenon of corona discharge, which is one type of plasma, to do the local cooling of an article. U.S. Pat. No. 4,210,847 designed an apparatus for generating an air jet for cooling application. U.S. Pat. No. 5,554,344 had a gas ionization device to do the cooling of zone producing chamber. U.S. Pat. No. 6,796,532 B2 used a plasma discharge to manipulate the boundary layer and the angular locations of its separation points in cross flow planes to control the symmetry or asymmetry of the vortex pattern.
However, none of the above patents are coupled to the heat sink, which is a fundamental apparatus for cooling electronic devices. Hence, what are needed are a method and an apparatus, to couple with heat sink fins to cool down electronic devices efficiently.

SUMMARY OF THE INVENTION

One embodiment of the present invention provides a plasma-driven cooling device couple to heat sink fins to induce the gas flow along the heat sink fins. The induced gas flow will remove the heat away from heat sink fin surface and therefore the heat source is cool down.
In one embodiment, the plasma-driven cooling device includes heat sink fin assembly, magnetic circuit assembly, and plasma actuator assembly. The heat sink fin assembly includes a plurality of heat sink fins. The magnetic circuit assembly includes ferromagnetic yokes and magnets. The plasma actuator assembly includes electrodes and dielectric pieces.
In one embodiment, each plasma actuator in the plasma actuator assembly may be separately controlled and powered, such as, by a controller and a power supplier, to provide different convective cooling rates at different locations on the heat sink fins.
In one embodiment, plasma-driven gas may flow in varied directions and the flow patterns may vary. The electrodes, heat sink fins, and dielectric pieces may have varied configurations and geometry.
In one embodiment, varied voltages may be applied to the electrodes to induce the gas flow to cool down the heat source. The applied voltages may have varied waveforms, frequencies, amplitude, phase shifts, and time period.
In one embodiment, the magnetic circuit assembly may have different configurations to provide magnetic field. The magnetic field will interact with electrical field and plasma to induce turbulent flow, and therefore, the heat source is cooled down.
In one embodiment, the electrodes may be populated in between heat sink fins, and when the voltages are applied to these electrodes, the induced ions gas flow may cool down the heat sink assembly.
In one embodiment, the sharp electrodes may be made along out-of-plane or in-plane direction.
In one embodiment, the plasma actuators may be populated in between heat sink fins, at the entrance of the heat sink fins, or at any locations to couple with heat sink fins assembly.
In one embodiment, the electrode traces may be layout with varied configurations and the sharp electrodes may be populated on the electrode traces.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention may be obtained when the following detailed description is considered in conjunction with the following drawings, in which:

FIG. 1 illustrates a plasma-driven cooling device coupled to heat transferring pipes and heat source, according to an embodiment;

FIG. 2 illustrates a plasma-driven cooling device, according to an embodiment;

FIG. 3 illustrates a plasma actuator assembly, according to an embodiment;

FIG. 4 illustrates the detailed view of a plasma actuator assembly, according to an embodiment;

FIG. 5 illustrates cross sectional view of a plasma actuator, according to an embodiment;

FIG. 6 illustrates a cross sectional view of plasma actuator, according to an embodiment;

FIG. 7 illustrates a cross sectional view of plasma actuator, according to an embodiment;

FIG. 8 illustrates cross sectional view of magnetic circuit assembly, according to an embodiment.

FIG. 9 illustrates a heat sink cooling using corona wind;

FIG. 10 illustrates a heat sink cooling using corona wind;

FIG. 11 illustrates a heat sink cooling using corona wind;

FIG. 12 illustrates a cross sectional view of the electrode on the heat sink cooling.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. Furthermore, note that the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not a mandatory sense (i.e., must). The term “include”, and derivations thereof, mean “including, but not limited to”. The term “coupled” means “directly or indirectly connected”.

DETAILED DESCRIPTION OF THE INVENTION

The invention generally relates to apparatus for cooling microelectronic devices or packages, such as microprocessors, and ASIC. Such systems and methods may be used in a variety of applications. A non-exhaustive list of such applications includes the cooling of: a microprocessor chip, a graphics processor chip, an ASIC chip, a video processor chip, a DSP chip, a memory chip, a hard disk drive, a graphic card, a portable testing electronics, a personal computer system.
Take laptop computer for example, conventional fans use a lot of space and energy. For this reason, the plasma-driven cooling device represents a way to increase their cooling capacity and make them more reliable and far quieter. Therefore the higher-performance chips that generate too much heat for current laptops can be used.
As used herein “plasma” is an ionized gas, a gas into which sufficient energy is provided to free electrons from atoms or molecules and to allow both species, ions and electrons, to coexist. Plasma is even common here on earth. A plasma is a gas that has been energized to the point that some of the electrons break free from, but travel with, their nucleus. Gases can become plasmas in several ways, but all include pumping the gas with energy. A spark in a gas will create a plasma. A hot gas passing through a big spark will turn the gas stream into a plasma that can be useful. Plasma torches like that are used in industry to cut metals.
As used herein “electrode” is an electrical conductor used to make contact with a metallic part of a circuit.
As used herein “dielectric piece” is a substance that is a poor conductor of electricity, but an efficient supporter of electrostatic fields. In practice, most dielectric materials are solid. An important property of a dielectric is its ability to support an electrostatic field while dissipating minimal energy in the form of heat. The lower the dielectric loss (the proportion of energy lost as heat), the more effective is a dielectric material. Another consideration is the dielectric constant, the extent to which a substance concentrates the electrostatic lines of flux. Substances with a low dielectric constant include a perfect vacuum, dry air, and most pure, dry gases such as helium and nitrogen. Materials with moderate dielectric constants include ceramics, distilled water, paper, mica, polyethylene, and glass. Metal oxides, in general, have high dielectric constants.
FIG. 1 illustrates a configuration of an electronic cooling device. Heat source 100 generates heat and the heat is transferred to the heat sink fin assembly 104, through an attachment component 101, heat transfer pipes 102, and heat sink base 103. The attachment component 101 couples with heat source 100 and heat transferring pipes 102. The heat transfer pipes 102 may be heat pipes, liquid cooling pipes, refrigeration pipes, and other heat transferring pipes. The heat sink fins assembly 104 is coupled to magnetic circuit assembly 105 and plasma actuator assembly 106. When the plasma actuator assembly 106, coupled with magnetic circuit assembly 105, is operating, the heat sink fins assembly 104 is cooled down, and therefore, the heat sink source 100 is cooled down. In another embodiment, the heat source 100 may directly couple to heat sink base 103 and heat sink fins assembly 104, without the need of attachment component 101 and heat transferring pipes 102.
FIG.2 is a closer look of the heat sink fins assembly 104 and plasma actuator assembly 106. In this configuration, heat sink fins assembly 104 is composed by a plurality of heat sink fins 109, and two plasma actuator assemblies 106 are couple to heat sink fins assembly 104 at its two ends. In one embodiment, the plasma actuator assembly 106 can be at any location in the system, such as in the middle of the heat sink fin assembly 104, and varied numbers of the plasma actuator assembly 106 may be used.
FIG. 3 illustrates a plasma actuator assembly 106 is coupled to heat sink fin assembly 104, and lead wires 107 are coupled to plasma actuator assembly 106. The power supplier and controller may power and control the plasma actuators on the plasma actuator assembly 106 through lead wires 107. In FIG. 3, the lead wires 107 are on top of the plasma actuator assembly 106. Lead wires 107 may be at any locations inside the plasma actuator assembly 106.
FIG. 4 illustrates plasma actuators assembly 106 is composed by electrodes 108 and dielectric pieces 110. The electrodes 108 may be coupled to dielectric pieces 110 on its two sides. When plasma actuator assembly 106 is operating, a plasma-driven gas flow is induced and the gas flow will pump into heat sink fins and therefore remove the heat from the heat sink fins surfaces. In this configuration, the plasma-driven gas flow is in y direction as shown in the figure. In one embodiment, all plasma actuators may be powered together, or each plasma actuator may be powered and controlled individually.
FIG. 5 a illustrates a cross sectional view of a plasma actuator assembly 106. In the figure, viewing from x direction, the plasma actuator assembly 106 contains two line electrodes 108, and the line electrodes 108 have triangular patterns on the edges. Plasma may be occurred between the patterns when appropriate voltages are applied to the electrodes 108. FIG. 5 b illustrates another cross sectional view of the assembly. In the figure, viewing from z direction, the plasma is occurred between electrodes 108, and the magnetic field direction 111 is going into paper. The interactions of plasma field, electrical field, and magnetic field, may induce a gas flow in y direction, as the arrows shown in the figure to cool down heat sink fins 109. In one embodiment, the shapes of the patterns on the edges of electrodes 108 may vary, such as the patterns may be flat shape, square shape, round shape, or other shapes, and the relative locations of the patterns may vary.
FIG. 6 illustrates several configurations of the electrodes 108 on the plasma actuator assembly 106. Besides that the shapes of the patterns can be varied in y-z plane, the figure shows that the patterns may have different shape in x direction. Therefore the patterns on the electrodes 108 may have 3D geometry. In one embodiment, varied number of electrodes may be coupled to plasma actuator assembly 106 to induce the gas flow and the relative locations among electrodes 108 may be varied. In a further embodiment, the applied voltages to the electrodes may be DC or AC, may be steady or transient, may be constant or varied amplitude, may have varied waveforms, and may have varied frequencies and phase shifts. In one application, as shown in FIG. 6,three pairs of electrodes may be powered, at time t, t+Δt, and t+2Δt to drive the gas flow, in sequential, into heat sink fin assembly 104. In another application, three pairs of electrodes may be powered simultaneously, with an AC and with a phase shift difference between each other, to induce a traveling plasma wave to drive the gas flow into heat sink fin assembly 104. In a further embodiment, a mixed combination of voltages may be used.
In one embodiment, the plasma actuator assembly 106 and heat sink fin assembly 104 may have varied configurations. FIG. 7 a illustrates a cross sectional view of plasma actuator assembly 106 whose gap is convergent, and the heat sink fins assembly 104 whose gap is divergent, toward +y direction. For FIG. 7 b, the heat sink fin assembly 104 has a fixed gap. Therefore, the gas flow is pushed into the heat sink fin assembly 104. In a similar mechanism for FIG. 7c, the gas is pushed out from heat sink fin assembly 106. By combining the pushing-in and pushing-out of the gas flow inside the heat sink fin assembly 106, the heat will be transferred away. In a further embodiment, the magnetic field strength at different locations may be varied, and the applied voltages to different electrodes 108 may be varied as well. In a further embodiment, varied configurations of plasma actuator assembly 106 and heat sink fin assembly 104 may be used, such as, aerodynamically streamlined configurations. However, all these variations shall be considered within the scope of the embodiments here.
The magnetic field will interact with electrical field and plasma field to induce the gas flow. FIG. 8 a illustrates a simple magnetic circuit, which has a yoke 112 and two permanent magnets 113. The yoke 112 is typically made of ferromagnetic materials, which have property of high magnetic permeability. The magnetic field between two permanent magnets may be used to interact with plasma and electrical field, and therefore drive the gas to flow into, or to flow out of heat sink fin assembly 104. In one embodiment, a big bulk magnetic circuit 105, for example like the one shown in FIG. 8 a, may be used to drive the all plasma actuators inside plasma actuator assembly 106. In another embodiment, each plasma actuator may have its own magnetic circuit. Several small magnets may be used for plasma actuators. FIG. 8 b and FIG. 8 c illustrate two possible arrangements. FIG. 8 a to FIG. 8 c are a non-exhaustive list of magnetic circuits. Therefore, any variations of magnetic circuits, such as, magnet geometry, magnet grade, magnet magnetization orientation, relative locations of magnets, and yoke geometry and material, should be considered within the scope of the embodiments here.
To couple the magnetic field with ions flow is one way of doing the cooling. However, using pure electrostatic or electro-dynamic field without magnetic field is sometimes more straightforward and FIG. 9 illustrates such an application. FIG. 9 a illustrates a simple heat sink device, which is composed by a heat sink base 200 and many heat sink fins 201. A layer of dielectric layer 202 may be attached, or deposited, or assembled on the top surface of heat sink base 200. The electrode traces 203 may be populated on the top surface of the dielectric layer 202. Furthermore, local sharp electrodes 204 may be populated at some spots on the electrode traces 203. The sharp electrodes 204, for example, may be needle-like configuration, which will result a high electric field at the tip when a voltage is applied to the electrode traces 2003. FIG. 9 c illustrates the coupling of the heat sink base 200, heat sink fins 201, dielectric layer 202, electrodes traces 203, and sharp electrodes 204. The ions flow generated at the sharp electrodes may be attracted to heat sink fins because the heat sink fins are generally electrically grounded. In one embodiment, each electrode trace 203 may be applied with one voltage or all electrode traces 203 may be connected together and applied with one voltage. By applying different voltages to electrode traces 203 can provide controlled cooling at different locations.
In FIG. 9, the electrode traces 203 are parallel to heat sink fins 201. In one embodiment, the electrode traces 203 may be with an angle with respect to heat sink fins. FIG. 10 a illustrates that the heat sink fins are segmented and FIG. 10 b illustrates the segmented heat sink fins 201 are coupled to dielectric layer 202 and electrode traces 203. In the configuration, the electrode traces 203 are perpendicular to heat sink fins. The ions flow direction will depend on the relative distance between sharp electrodes 204 and heat sink fins. In on embodiment, the ions flow may flow in out-of-plan direction and also in in-plan direction. In another embodiment, the magnitude, phase, and frequency of the applied voltages to each electrode traces 203 may be controlled to manipulate the ions flow direction in order to achieve the desired flow field. Furthermore, the dielectric layer 202 and electrode traces 203 may be located outside but near the heat sink fins assembly, as shown in FIG. 10 c and FIG. 10 d. The big black arrows shows the ions induced gas flowing into the heat sink assembly, the heat sink fins are bounded by heat sink base 200 and heat sink cover 205.
FIG. 11 a illustrates the heat sink fins 201 may be configured to be long cylinder populated on a heat sink base 200. FIG. 11 b shows a top view of the cylindrical heat sink fins 201 and sharp electrodes 204. The relative distance among sharp electrodes 204 and cylindrical heat sink fins 201 may be manipulated to obtain desired flow field. In one embodiment, the routing 206 of the electrode traces 203 may be configured to any patterns, and not necessary to be straight lines.
FIG. 12 a illustrates a cross sectional view of the assembly. The cross section is in X-Z plane. In one embodiment, the tip of the sharp electrode 204 may be made of a combination of copper, nickel-iron, chromium, or precious metals, such as yttrium, iridium, platinum, tungsten, or palladium, as well as the relatively prosaic silver or gold. The sharp tip may be extruding in out-of-plan direction as shown in FIG. 12 a, or may be in in-plane direction as shown in FIG. 12 b, which is in X-Y plane. The in-plane electrode traces 203 are easier for manufacturing. In one embodiment, the dielectric layer 202 may cover the electrode traces 203, as shown in FIG. 12 c.
Therefore, this invention discloses a method and apparatus for cooling electronic devices. The method and apparatus includes a plurality of heat sink fins forming a heat sink fin assembly, a magnetic circuit assembly and a plasma actuator assembly. In one exemplary embodiment, the magnetic circuit assembly and plasma actuator are coupled to heat sink fin assembly, and the magnetic circuit assembly and plasma actuator assembly may be at the inlet, outlet, or any locations of the heat sink fin assembly. In another exemplary embodiment, the plasma actuator assembly includes a plurality of plasma actuators, and plasma actuators include electrodes and dielectric pieces. In another exemplary embodiment, appropriate voltages can be applied to the electrodes on the plasma actuators to induce a gas to flow into or to flow out of heat sink fin assembly, and therefore remove the heat from heat sink fins surface. In another exemplary embodiment, the applied voltages to electrodes can be DC or AC, steady or transient, fixed or varied amplitude, fixed or varied frequency, with or without phase shift difference, and may have different waveforms. In another exemplary embodiment, the plasma actuator assembly may be powered and controlled by power suppliers and controllers, and all plasma actuators on the plasma actuator assembly may be powered all together, or each plasma actuator on the plasma actuator assembly may be powered and controlled individually, to cool down the heat sink fin assembly. In another exemplary embodiment, the electrodes may have varied patterns, and the patterns may have varied geometry, and the relative relocations among electrodes and patterns may be varied. In another exemplary embodiment, the heat sink fin assembly and plasma actuator assembly may have varied configurations; and the configurations may be used, to push the gas into heat sink fin assembly. In another exemplary embodiment, the applied voltages on the electrodes may be arranged to induce a traveling plasma wave, and the traveling plasma wave may be used to push the gas into heat sink fin assembly, and to push the gas out from heat sink fin assembly. In another exemplary embodiment, the magnetic circuit assembly includes yokes and magnets, and the yokes and magnets may have varied configurations. In another exemplary embodiment, the yokes and magnets may have varied geometry, varied grade, varied materials compositions, varied magnetization orientation, and varied relative locations. In another exemplary embodiment, the cooling apparatus may couple to heat source directly, or couple to heat source through heat transferring pipes and attachment components. In another exemplary embodiment, the transferring pipe may be heat pipe, liquid cooling pipe, refrigeration cooling pipe, or other heat-transferring pipe. In another exemplary embodiment, the apparatus further comprises thermal sensors coupled to heat sink fin assembly, wherein the thermal sensors are operable to measure the temperatures on heat sink fin assembly, and based on the measured temperatures, the power supplier and controller can command plasma actuators to adjust the cooling rate accordingly. In another exemplary embodiment, the magnetic circuit assembly is to provide a magnetic field, and wherein the magnetic circuit can be made of permanent magnets or electromagnets. In another exemplary embodiment, the heat source can include a microprocessor chip package; a graphics processor chip package; an ASIC chip package; a video processor chip package; a DSP chip package; a memory chip package; a hard disk drive; a power supply; or a graphic card; and any other heat sources within the electronic system. In another exemplary embodiment, the gas can include plasma, air, nitrogen, oxygen, and other fluids. In another exemplary embodiment, the dielectric material can include air, vacuum, Teflon, Kapton, and other materials. In another exemplary embodiment, the electrodes material can include gold, copper, nickel, tungsten, and other electrically conductive materials. In another exemplary embodiment, the heat sink fin assembly and plasma actuator assembly may be manufactured with different scale, such as, a bulk scale, a micro-scale, or a nano-micrometer scale.
Although the present invention has been described in terms of the presently preferred embodiment, it is to be understood that such disclosure is not to be interpreted as limiting. Various alternations and modifications will no doubt become apparent to those skilled in the art after reading the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alternations and modifications as fall within the true spirit and scope of the invention.

Claims

1. A method and apparatus for cooling electronic devices, comprising:

a plurality of heat sink fins forming a heat sink fin assembly;

a magnetic circuit assembly;

a plasma actuator assembly;

2. The cooling device of claim 1, wherein the magnetic circuit assembly and plasma actuator are coupled to heat sink fin assembly, and the magnetic circuit assembly and plasma actuator assembly may be at the inlet, outlet, or any locations of the heat sink fin assembly;

3. The cooling device of claim 1, wherein the plasma actuator assembly comprising a plurality of plasma actuators, and plasma actuators comprising electrodes and dielectric pieces;

4. The cooling device of claim 3, appropriate voltages can be applied to the electrodes on the plasma actuators to induce a gas to flow into or to flow out of heat sink fin assembly, and therefore remove the heat from heat sink fins surface;

5. The cooling device of claim 4, wherein the applied voltages to electrodes can be DC or AC, steady or transient, fixed or varied amplitude, fixed or varied frequency, with or without phase shift difference, and may have different waveforms;

6. The cooling device of claim 1, wherein the plasma actuator assembly may be powered and controlled by power suppliers and controllers, and all plasma actuators on the plasma actuator assembly may be powered all together, or each plasma actuator on the plasma actuator assembly may be powered and controlled individually, to cool down the heat sink fin assembly;

7. The cooling device of claim 3, wherein the electrodes may have varied patterns, and the patterns may have varied geometry, and the relative relocations among electrodes and patterns may be varied;

8. The cooling device of claim 1, wherein the heat sink fin assembly and plasma actuator assembly may have varied configurations; and the configurations may be used, to push the gas into heat sink fin assembly;

9. The cooling device of claim 5, wherein the applied voltages on the electrodes may be arranged to induce a traveling plasma wave, and the traveling plasma wave may be used to push the gas into heat sink fin assembly, and to push the gas out from heat sink fin assembly;

10. The cooling device of claim 1, wherein the magnetic circuit assembly comprising yokes and magnets, and the yokes and magnets may have varied configurations;

11. The cooling device of claim 10, wherein the yokes and magnets may have varied geometry, varied grade, varied materials compositions, varied magnetization orientation, and varied relative locations;

12. The cooling device of claim 1, wherein the cooling apparatus may couple to heat source directly, or couple to heat source through heat transferring pipes and attachment components;

13. The cooling device of claim 12, wherein the transferring pipe may be heat pipe, liquid cooling pipe, refrigeration cooling pipe, or other heat transferring pipe;

14. The cooling device of claim 1, further may comprises thermal sensors coupled to heat sink fin assembly, wherein the thermal sensors are operable to measure the temperatures on heat sink fin assembly, and based on the measured temperatures, the power supplier and controller can command plasma actuators to adjust the cooling rate accordingly;

15. The cooling device of claim 1, wherein the magnetic circuit assembly is to provide a magnetic field, and wherein the magnetic circuit can be made of permanent magnets or electromagnets;

16. The apparatus for cooling an electronic device of claim 1, wherein the plasma actuator assembly may comprise a plurality of electrode traces populated on a dielectric layer and couple to a heat sink base.

17. The apparatus for cooling an electronic device of claim 16, wherein the electrode traces may have sharp electrodes populated on them.

18. The apparatus for cooling an electronic device of claim 16, the voltages applied to the electrode traces may be varied to induce the ions flow to flow in-plane and out-of-plane directions, and therefore cooling down the heat source.

19. The apparatus for cooling an electronic device of claim 16, wherein the electrode traces may be located at the entrance, at the exit, or at any location inside the heat sink assembly.

20. The apparatus for cooling an electronic device of claim 16, the heat sink fins may have varied configurations, and the electrode traces may have varied layout populated on the dielectric layer.