Magnetohydrodynamic (MHD) Propulsion - What Is It? #magnetohydrodynamics #mhd #aerospace #asteronx

[Music] mhd propulsion what is it mhd propulsion is the breakthrough that we humanity needs in order to master getting into space after all iris astronex and the eos project cannot be a massive space project if we cannot first get into space right since mhd is so important for the future success of iris astronex the aos project and therefore humanity as a whole we have decided to make this whole video dedicated specifically to this subject first mhd is an acronym it stands for magneto hydrodynamics but of course this statement simply leads one to ask what is magnetohydrodynamics from wikipedia magnetohydrodynamics is also called magnetofluid dynamics or hydromagnetics which is the study of the magnetic properties and behavior of electrically conducting fluids while magneto hydrodynamics technically refers only to water hence hydro the meaning has evolved over time and has come to refer generally to all electrically conducting fluids [Music] one thing all these craft have in common is that they all use some form of field drive technology this page outlines the evolutionary steps we will take in researching and developing field drive technologies starting with the electrodynamic drone and mhd aerospacecraft interplanetary craft and ultimately starships [Music] now let's get back to what this video is about what is mhd propulsion mhd propulsion is a form of propulsion that utilizes electromagnetic forces to move fluids such as ionized air plasmas sea water etc without the need for propellers or any other kind of airfoil in fact without the need for any moving parts whatsoever specifically the working principle of mhd propulsion involves the acceleration of an electrically conductive fluid by the lorentz force which is the repulsive magnetic force appearing wherever an electric current is perpendicular to a magnetic field what typically happens in a conversation involving somebody explaining what mhd propulsion is one begins to confuse mhd propulsion with ion wind propulsion and if one does not confuse these two categories of propulsion with one another one at least is immediately thinking and or mentioning iron wind propulsion within the same conversation so in a video like this it is important to explain the difference between eye and wind propulsion and mht propulsion before we go any further ion wind propulsion or more generally electrohydrodynamic propulsion which can also be called ehd propulsion works by accelerating ionized air or another electrically conductive fluid utilizing only electric fields instead of magnetic fields speaking generally ehd ion wind propulsion has a lower thrust given the same volume compared to mhd propulsion in technical jargon this is called power density while there is a distinct difference between ehd propulsion and mhd propulsion in many cases the two can overlap and may even be used together in the same vehicle this explanation can be even more easily understood if one were to stop and consider the meaning of the term ironwind ion wind or as it is sometimes called electric wind is produced when an intense electric field causes a breakdown of air forming a cloud of light charged ions or electrons depending on the polarity of the field the ions electrons are repelled by the electric field and each other expanding outwards or moving towards an electric field of opposite polarity in the process the ions or electrons collide with neutral air molecules creating a wind away from the initial electric field either outward or toward another electric field of the opposite polarity [Music] there is one more thing we need to explain in order that there is no confusion or misunderstanding electro hydrodynamics ehd is not the same as electrodynamics the field of electrodynamics includes both ehd and mhd so all forms of ehd propulsion and mhd propulsion are also electrodynamic propulsion but not all forms of electrodynamic propulsion are necessarily ehd or mhd electrodynamic propulsion is a useful term to distinguish mhd in a conductive physical fluid from mhd type propulsion in a non-physical medium such as the quantum vacuum [Music] now let's move on to the next section of this video mhd propulsion fundamentals to begin let us remind ourselves of how wings work if you research the subject how wings work on your own you will eventually discover that there is no one single answer to explain how they work however you will find all explanations revolve around the concept of creating a pressure differential between the top and bottom of a wing with the aim being to increase the relative pressure on the underside of said wing leading to an effect called lift to clarify the exact mechanism of lift really depends on the specific circumstances flight environment wing design etc [Music] different mechanisms must be at work in different situations or even multiple mechanisms may be active at the same time or for the same wing or airfoil at different times lower or higher speeds etc now that we are finished re-examining how wings work it is time to consider the meaning of the term lorenz force what is the lorenz force the lorenz force is the repulsive force between magnets or more specifically it is a force that arises when electric current is at a right angle to a magnetic field this occurs even for permanent magnets such as ordinary fridge magnets in this case the currents involved are created by the magnets themselves as opposed to being created separately as we will discuss with regards to mhd propulsion these currents are also generally quite weak it is worth noting briefly that the repulsive force you feel when trying to push a pair of magnets together is in fact their lorentz force a fluid can be accelerated decelerated or its pressure increased or decreased via the lorentz force in order for the lorentz force to act on a fluid the fluid must either be conductive already or made conductive in the moment such as by ionization or the addition of electrolytes in the case of mhd propulsion oppositely charged electrodes are used to create the needed electric current through the fluid a magnetic field is then passed at a right angle to it giving rise to the lorenz force accelerating or decelerating the fluid if the fluid is already moving a lorentz force can be used to either accelerate the fluid further and thereby decrease its pressure or to decelerate the fluid and so increase its pressure if you are looking for an even more detailed description on the lorentz force you can easily find one on wikipedia we will put a link to said description in the description section of this video below we will also leave a link to a comic book style explanation of how mhd propulsion works by jean-pierre petit despite the comic book style the explanations given are very accurate and thorough okay so far we have covered this what abhd propulsion is how it works and covered some of the fundamentals of mhd propulsion now let's move on to the next part of this video how mhd propulsion functions in an atmosphere now remember electric and magnetic fields can only act on a conductive medium therefore to operate in an atmosphere an mhd propelled vehicle must first ionize the air this can be done in one of several ways but one of the most efficient methods is known as high frequency pulse discharge or hf pulse discharge for short this is where an alternating current at radio to microwave frequency or higher produces electromagnetic radiation and fields that ionizes air or other gases very efficiently the ionized air then forms a conductive sheath just off of the surface which absorbs all or most of the emitted radiation once the air is ionized it can be moved via electromagnetic forces such as the lorentz force or via an ion wind effect this is where ehd propulsion ion wind propulsion and mhd propulsion can sometimes be confused with each other because in some vehicle designs both forms of propulsion can be implemented on the same vehicle to maximize efficiency also different versions or iterations of a vehicle might use only iron-wind propulsion only mhd propulsion or both the airflow created by mhd acceleration or ion wind is directed over an airfoil creating lift this can be air foils in the form of more or less conventional wings alternatively a saucer shaped coenda effect airfoil provides greater lift than a conventional wing and is well suited to mhd or ehd that creates a wind without the need to move the entire vehicle nor even the airfoil think of the saucer airfoil as a wing wrapped around the vehicle mhd propulsion can also come in the form of an mhd plasma jet engine with a very high power density that is a small device will produce very high thrust this is in sharp contrast to iron wind thrusters which have a very low power density and therefore typically very low thrust [Music] mhd propulsion in space the simplest and easiest form of mhd space propulsion are mhd jet engines or rather mhd rocket engines these can utilize the lorenz force to directly accelerate a cold plasma alternatively radio frequency discharge or microwaves can be used to superheat a gas into a hot plasma state which is then kept off the walls via magnetic fields which involves lorenz forces the hot plasma is then allowed to escape as with a conventional chemical rocket engine there are advantages and disadvantages to both both can have a high thrust and a high efficiency though using a hot plasma will generally give a higher thrust but lower efficiency unless the plasma is extremely hot as infusion temperatures in the not so distant future we will utilize mhd space propulsion that pushes off of the quantum vacuum directly to avoid confusion with strictly atmospheric or water-based mhd we sometimes call this electrodynamic propulsion empty space is not actually empty it is filled with extremely short-lived particles usually called virtual particles however the term virtual particles is a misnomer and historical misnaming as these particles are not fundamentally different than ordinary particles the only difference between the so-called virtual particles and ordinary particles is lifetime the virtual particles are exceedingly short-lived most things happen over very long periods of time in comparison so the activity of the virtual particles cancels out and can be safely ignored however for electromagnetic fields or radiation with a very high energy very high frequency or both high energy and high frequency these virtual particles cannot be ignored therefore ultra short and intense electromagnetic pulses can interact with these abundant and ubiquitous particles particularly the short-lived electrons and anti-electrons also known as positrons are kind of antimatter these ultra short and intense electromagnetic pulses can then be used to create lorenz forces on the electron positron plasma creating thrust i hope this video helps you obtain a deeper level of understanding on the subject of mhd propulsion stay tuned for more videos and more sections within future videos with more information on the subject as time goes on and as always keep wondering about space

Channel: AsteronX

Views: 426,058

Keywords: AsteronX, IRIS-AsteronX, IRIS, International Space Institute for Space, MHD, EHD, magnetohydrodynamic, electrohydrodynamic, VASIMR, pulse inductive thruster, ionocraft, ion-propelled craft

Id: vvLT7x47x5M

Length: 15min 20sec (920 seconds)

Published: Wed Aug 31 2022