A New Fusion Project Fires Up
MIT and Columbia University are trying a new approach to nuclear fusion with the Levitated Dipole Experiment
By Mara E. Vatz
Deep in the bowels of Building NW-21, a former Nabisco facility on the west side of the MIT campus, is a three-story-tall, five-meter-wide metal structure that resembles a flying saucer. Inside it is a 560-kilogram, doughnut-shaped superconducting magnet that will float 1.5 meters off the ground when another magnet above it is charged. This is the playground of the Levitated Dipole Experiment (LDX), a collaboration between MIT and Columbia University dedicated to developing a new approach to nuclear fusion.
The LDX project, which began in 1998 with funding from the U.S. Department of Energy, is a newcomer to the field of fusion. Down the hall in the same building, Alcator C-Modthe third in a series of MIT fusion projects that began in 1971has a much larger staff and budget. But the LDX, unlike Alcator, isnt trying to create fusion conditions or a fusion deviceyet. For now, its researchers are focused on a fairly basic question that could have far-reaching results: how stable is magnetically pulled plasma?
Realizing the Fusion Dream
Fusion could someday provide an ideal alternative to fission, the type of nuclear reaction used in todays nuclear power plants. For one thing, fusion runs on hydrogen, a virtually limitless fuel, while fission requires uranium or plutonium, rare elements that carry the added risk of nuclear-weapons proliferation. And while a malfunction in a fission reactor can have devastating consequences, fusion reactions are by nature extremely difficult to sustain; they therefore pose little threat of propagating out of control and causing large-scale disasters.
But a practical method for producing fusion reactions has long eluded scientists. Ever since the hydrogen bomb was exploded in 1952, explains Jay Kesner, a leader of the LDX projects research team, people have been trying to learn how to confine plasma and make energy from hydrogen fusionand to do it in a controlled way so that you can make electricity. One of the key problems is that fusion fuelplasma consisting of hydrogen nuclei that have been stripped of their electronsis extremely difficult to confine and control.
When hydrogen plasma reaches sunlike temperatures, nuclei can collide and undergo nuclear fusion reactions. The nuclei of two hydrogen isotopes meld to produce a helium nucleus along with a highly energetic neutron, which can be captured and used to heat water. To ensure that the hydrogen nuclei collide, you have to hold the plasma together and make it very dense and very hot, says Kesner.
In the most successful fusion projects to date, including Alcator, magnetic coils on the outside of a doughnut-shaped chamber create a magnetic field that tends to steer the moving plasma particles along fixed trajectories. But that can get tricky. Plasma, like a gas, will expand into the space available. It also has the ability to take on collective motionthat is, to move in waveswhich can cause the particles to fly off the magnetic-field lines and lose energy by colliding with the chamber walls. To further complicate matters, a hot plasma creates its own magnetic fields that counteract the confinement fields applied by the external magnets. [Fusion] is one of these phenomena that, the closer you get, the harder it gets, Kesner says.
A Magnetic Star
The LDX may make possible a significant improvement in plasma confinement. Rather than using external magnets to push on the plasma, the LDX uses an internal dipole magnet to restrain it. The resulting plasma cloud will resemble a star, which is just a giant natural fusion device held together by gravity, explains Darren Garnier, PhD 96, a Columbia research scientist who heads experimental operations for the LDX project. But instead of using gravity to confine the plasma, the LDX will use a magnetic field. Basically, were trying to make a magnetic star, Garnier says.
The LDX is not the first fusion project to confine plasma by pulling on it, but it will be the first to use a floating magnet. In earlier, nonlevitated-dipole experiments, the magnets physical supports interfered with the magnetic-field lines and therefore with the confined plasma, causing a significant loss of energy. The LDXs floating dipole will have no such interference.
According to theory, a fusion reaction in which plasma is pulled into place should be more stable than one in which its pushed. The LDX groups initial experiments, which began last fall and still rely on a physically supported dipole, are beginning to test that theory. The real test will come this summer when the researchers levitate the dipole for the first time. Everyone is still waiting with bated breath for our levitation results, says Garnier. If all goes well, within a few months the scientists will know whether their design could help make fusion energy a reality.
Janet Sonenberg helps students enhance their theater performances
By Tracy Staedter
The first time that electrical-engineering and computer science major Manish Goyal 96, Mng 98, auditioned for a play, he felt extra nervous. Sure, it was his first audition, but it was more the prospect of working with the plays director, Janet Sonenberg, that filled him with anxiety. He had heard that she inspired strong emotions, ranging from love to fear, and as she coolly observed him from behind a pair of dark glasses, he didnt know what to expect. While he didnt get the part, in the nine years since that encounter, he has come to know Sonenberg well by taking her classes, participating in a workshop, and asking her for advice. Its amazing how quickly I grew to crave that cool, unnerving, piercing gaze that once made me feel so transparent, he says.
Its a sentiment other students have expressed and one of the reasons Sonenberg has become a successful teacher, artist, and researcher at MIT. Since joining the faculty in 1992, Sonenberg has directed five plays, served as director of theater arts, published two books, received a Baker undergraduate teaching award, and been named a MacVicar Faculty Fellow. Her most recent book, Dreamwork for Actors, describes a technique she developed that helps actors tap their imaginations. I work with the assumption that all products of the imagination are valuable, says Sonenberg.
The technique, which she devised with Jungian analyst Robert Bosnak, allows actors to use their dreams to enhance their performances on stage. After several rehearsals, the actor focuses on a compelling moment in the play and derives a visual image and a corresponding physical sensation that characterize it, creating what Sonenberg calls an incubation image. That night, before falling asleep, the actor concentrates on the incubation image for a minute and in the morning writes down any dreams that came in the night. Though the dreams, on their surface, may not involve the play, Sonenberg believes that they can connect the world of the character to experiences in the actors personal life. Next, the actor associates physical sensations with the dream images and recalls them just before a performance. It sets up a network of imagination that starts firing, says Sonenberg.
She has used the technique with success on previous plays and plans to use it in her current project, a play she is creating in collaboration with Englands Royal Shakespeare Company. The play will explore a period in English history between 1642 and 1660 when, despite the Puritan Parliaments ban on theater, scientists such as chemist Robert Boyle began staging public experiments, helping speed the transition from theoretical to experimental science. Im interested in what theater has to say about science and what science has to say about theater, says Sonenberg, who happens to be married to Rodney Brooks, director of MITs Computer Science and Artificial Intelligence Laboratory.
Her interest in science makes her well suited to teach at MIT, says Alan Brody, associate provost for the arts. Shes able to understand where the engineer and the scientist [are] coming from and to speak to them in their own language, he says. For Sonenberg, teaching theater to engineering majors has its own rewards. They are uniquely imaginative, she says. And if nothing else, she hopes they come away with a method for learning. Its about getting people to be true to themselves, she says.
Slip Sticks Land at MIT
More than 600 historic slide rules have found a new home at the MIT Museum
By Lisa Scanlon
Slide rules excite interest and even passion at the Institute, especially among engineers of a certain age, says MIT Museum science and technology curator Deborah Douglas. Now, thanks to a recent donation of more than 600 historic slide rules by South Hadley, MAbased InteliCoat Technologies, the museum will be able to share the history of this beloved calculating device with a wider audience.
The collection was assembled by Keuffel and Esser of Hoboken, NJ, which was one of the largest manufacturers and distributors of slide rules in the United States from the 1870s until around 1976, when it got out of the business because of the popularity of electronic calculators. The collection, which found its way to InteliCoat after a series of mergers and acquisitions, includes rules that Keuffel and Esser made throughout this hundred-year span, as well as competitors rules.
MIT Museum curators are particularly excited about the collection because it illustrates how Keuffel and Esser experimented with different designs and styles, and how its clientele changed over the years. In addition to its standard engineers rules, the company developed a series of specialty rules. For example, the collection includes a residential building cost slide rule that estimates the cost of building a house given its square footage and construction materials. Other treasures include a rare three-sided brass rule made in the late 1800s and a 2.5-meter-long demonstration rule for teachers.
The museum is just starting to document the rules, which it received last summer. Pending funding, Douglas hopes to open an exhibition in about two years. She is sure the collection will attract attention from alumni who still have sentimental attachments to slide rules, and she hopes it will also intrigue the calculator generation. Almost everything in the modern world was built in some way using one of these, says Douglas. Whether its a sewer pipe or the space shuttle or a bridge or a radio, theyre all designed by people who used this tool for making general calculations.
Researchers find that magnesium is crucial to cognitive functions
By Lisa Scanlon
Were all used to hearing about the importance of getting enough calcium, iron, and vitamins, but magnesium is completely off most peoples nutritional radar. That could soon change, thanks to research at the Picower Center for Learning and Memory that suggests that the mineral found in foods such as avocados and green, leafy vegetables plays an important part in learning and memory.
Scientists have long known that when the brains synapses lose their plasticity, or ability to change, the brain has a harder time learning and remembering. This deterioration happens naturally as people age. Less clear, however, has been exactly what causes these changes. But now, associate professor Guosong Liu and postdoctoral associate Inna Slutsky have developed a theory about what causes loss of plasticity in the brain.
First, the researchers surmised that plasticity is affected by random neural activity or noise within the brain. The more random, unstructured stuff in your brain, the less the brain is capable of encoding new information, Liu says. Liu and Slutsky set out to find molecules that could help the brain suppress this background noise. They found that magnesium did just that. In the researchers experiments, cultures of rat neurons that received high levels of magnesium were far more plastic than those that did not.
Liu hopes that within a year, clinical trials will begin to study the effects of magnesium on human brains. In the longer term, he imagines new drugs that might enhance or dampen a persons memory; you might, for example, choose to take a pill to sharpen your memory before leaving for a long-anticipated vacation. For now, Liu is confident that the research will put magnesium on the map.
Lincoln Lab Investigation on Hold
Postol and colleagues spar
Nearly four years ago, MIT physicist Theodore A. Postol approached Institute officials demanding that they investigate an alleged case of scientific fraud at the Lincoln Laboratory, related to tests of a U.S. military missile defense system. MIT commissioned an inquiry into Postols allegations and authorized an investigation in January 2003. But in December 2004, administrators announced that they had been unable to conduct the investigation because the U.S. Missile Defense Agency has classified all information relating to the allegations, including the results of the Institutes internal inquiry. Postol insists that there is still enough public information for the investigation to go forward, and he remains committed to his cause despite his removal from one MIT program.
Postol alleges that Lincoln Laboratory misrepresented a failed U.S. missile defense test as a success to federal agents who were investigating it for the possibility of research fraud. The test at issue was one of two critical tests performed in the late 1990s to determine if the current National Missile Defense system could distinguish warheads from decoys. The system will have only a small number of interceptors, so it could be easily defeated if an adversary launched credible decoys along with warheads.
Integrity in research and scholarship is a bedrock principle of MIT, and we give serious attention to allegations of violation of that principle, Institute officials said in the December statement. In this case, MIT has worked for nearly three years to meet this responsibility but has been unsuccessful in obtaining access to classified materials essential to complete this process.
Postol is not deterred, but his concentration on this issue has alienated him from his colleagues in the Security Studies Program, who forced him out of their group last summer. Program director Harvey Sapolsky classifies the problem as interpersonal. We couldnt work with him, says Sapolsky. Postol, who remains a tenured professor in the Program in Science, Technology, and Society, claims his removal from the Security Studies Program was in retaliation for his activism with respect to the research fraud issue.
In its December statement, MIT says it will continue to seek access to the classified materials it deems necessary for the investigation. But Postol isnt likely to rest until an investigation takes place, regardless of whether the classified materials are made available. MIT should not be promulgating scientific fraud, and thats whats going on here, he says.
Marshall and Rhodes scholars
Half a dozen MIT students with interests as varied as HIV research, economics, and astrophysics are headed to England this fall on Rhodes and Marshall scholarships. Both provide two years of full funding for graduate research, the Rhodes at the University of Oxford and the Marshall at any university in the United Kingdom. MIT has not had as many as six students selected for these prizes since 1999.
The Rhodes scholarship program offers two-year Oxford scholarships to some 89 students from more than 20 countries each year. Scholarswhose predecessors include former U.S. president Bill Clinton and basketball great Bill Bradleymust not only have achieved academic excellence but also, as founder Cecil Rhodes put it, esteem the performance of public duties as [their] highest aim. Marshall scholarships were initiated by the U.K. Parliament in 1953, as a gesture of thanks to the United States for aid received under the Marshall Plan. The program awards at least 40 scholarships to U.S. students each year and allows students to attend any U.K. university.
Laurel Yong-Hwa Lee 05, named by Glamour magazine as one of its Top 10 College Women in 2004, will use her Rhodes scholarship to pursue a doctorate in clinical medicine at Oxford. My potential project will be part of an effort to investigate the human immune response to HIV viral infection, Lee says. Between shifts in the laboratory, she hopes to continue rowing and attend opera performances at the Royal Opera House.
Jessica Lee 05, a Marshall scholar, has enrolled in a one-year program in biodiversity, conservation, and management at the University of Oxford. Her interest in the field stems in part from her Undergraduate Research Opportunities Program project on the molecular ecology and genomics of viruses that infect marine cyanobacteria. She plans to spend her spare time doing competitive ballroom dancing. As she says, England is really the place to do ballroom dance.
Brian Mazzeo 05, also a Marshall scholar, will pursue a two-year degree in engineering at the University of Cambridge. Mazzeo took two years off from his undergraduate studies to do missionary work in Bolivia and then returned to MIT to focus on engineering, an early passion. When I was a freshman in high school, I built a roller coaster out of toothpicks that was as tall as I was, he says. His research at Cambridge will focus on modeling and processing electronic materials.
Virginia Corless 05 will use her Marshall scholarship to continue her undergraduate research in astrophysics; shell pursue a doctorate at the University of Cambridge. She also maintains an interest in development studies. She minored in applied international studies and taught molecular and experimental biology to high-school students at Shi Shi High School in Chengdu, China, for four weeks in 2002 as part of MITs China Educational Technology Initiative.
Betsy Masiello, a 2003 Wellesley College graduate earning a masters degree in technology and policy at MIT, will study financial economics at Oxford as a Rhodes scholar. Her MIT research focused on economic and technical aspects of identification, such as the authentication tools that verify peoples identities online. Masiello previously worked for the National Security Agency.
Javed Samuel 04, Mng 05, a Rhodes scholar who completed a master of engineering degree in the Department of Electrical Engineering and Computer Science, will study mathematical modeling at Oxford, focusing particularly on financial applications. He is from Vieux Fort, Saint Lucia, and is excited to seek out famous cricket grounds when he finally arrives in England.
Q&A: Sherry Turkle
Reflecting on mind and machine
By Kathryn Beaumont
Lose your cell phone, and your dependence on technology becomes all too apparent; but only 10 years ago, you could drive from home to work without talking to a soul. How and why do we form such intense attachments to new technologies? Thats a question Sherry Turkle, Abby Rockefeller Mauzé Professor of the Social Studies of Science and Technology and the director of the MIT Initiative on Technology and the Self, has been researching for more than 30 years. Here she offers some insights into her work.
You are a psychologist. How did you first become interested in technology and its relationship to psychology?
I came to MIT in the late 1970s and was struck by the intensity of the relationships my students had with technology. I had never thought much about computers as anything more than information processors. Once here, I met students and colleagues who claimed that building and programming computers was the most powerful intellectual and emotional experience of their lives. More than this, they used computer language to talk and to think about their minds. In the early years of the personal-computer culture, these new objects carried a conversation about mind, free will, what was alive and not alive, out of philosophy seminar rooms and into everyday life. I began to study computers as evocative objects for thinking about thinking.
Why did you form the MIT Initiative on Technology and the Self?
I wanted to provide an opportunity for a conversation about technology that put the focus on technology and our inner livesnot what technology does for us, but what it does to us, to our ways of seeing the world, to our ways of seeing ourselves.
How has your research changed over the years?
My most recent research has focused on relational artifacts, software agents and artificial creatures that are designed to form social relationships. For years I studied the computer as Rorschach, as a blank screen onto which people project personal meaning. With relational artifacts, the Rorschach metaphor breaks down in significant ways. Relational artifacts present themselves as having states of mind that are affected by their interactions with people.
One of the most striking results of this work is to find that the killer app for a new generation of information technology may well be nurturancepeople drawn to computational creatures because they feel themselves to be in relationships with them. People want to feel connected to new forms of artificial life. So, for example, when children take care of robotic creatures, when these creatures seem to respond to that care, children not only attribute life to that creature but think about its aliveness in terms of the kind of relationship they have formed with it.
How are peoples current relationships with technology different from when you started researching them?
Today, the situation is more complex. New computational objectspersonal digital assistants, cell phones, laptopsare even more intimate partners to their users, more like thought-prosthetics than simple tools. Yet even as the subjective side to the technology has become more apparent, its ubiquity has led to a cultural experience of it as background noise.
What do you hope will result from your work?
The goal in all of my work is to bring a richer discourse about objects to science and technology studiesone that is developmental, psychodynamic, and steeped in the experience of peoples daily lives and relationships.
How brains are wired to recognize mugs
By Lisa Scanlon
In research that could help people who suffer from prosopagnosia, the inability to recognize faces, scientists at MITs McGovern Institute for Brain Research are studying how the brain processes facial features.
Nancy Kanwisher, a professor of cognitive neuroscience, and postdoc Galit Yovel focus on an area of the brain called the fusiform face area (FFA), which, as its name might suggest, has long been suspected to play a role in face recognition. Kanwisher and Yovel have investigated whether the FFA works exclusively to process faces or whether it processes spatial relations among parts of other objects as well. Its known that faces are processed differently than other objects, says Yovel. The question is how differently.
Kanwisher and Yovel instructed volunteers to identify differences between pictures of faces that were identical except for the spacing of their features and between pairs of faces that shared most, but not all, of their features. The subjects also examined houses with variously spaced windows or doors and with different windows or doors. Because the FFA was found to be more active when subjects were looking at faces than when they were looking at houses, regardless of how the objects differed, the researchers believe the FFA is wired specifically to recognize faces. Yovel says understanding the FFA could inspire training techniques to help people with prosopagnosia.
A Pilgrimage to India
A Fulbright grant sends an MIT writer home to study mountain lore
By Tracy Staedter
When stephen alter was working on his travel book Sacred Waters: A Pilgrimage up the Ganges River to the Source of Hindu Culture, he trekked over mountains and through deep valleys to the holy rivers headwaters, as pilgrims have done for centuries. During his journey, he explored the myths and traditions associated with the Hindu canon but also looked into local stories connected to bird calls, trees, medicinal herbs, and even rocks. I realized very clearly that there was a whole body of tales in folklore specific to the mountains, says Alter, who has authored eight books and is now writer-in-residence at MIT, where he has taught for nine years. He began to wonder how the stories he heard varied, if at all, from place to place, and he knew that he would have to return to India to find the answer.
That time has come. Last fall, Alter received a Fulbright grant to spend from January to October 2005 researching folktales of the Himalayas. Additional funding from the American Institute of Indian Studies in Chicago will give Alter a total of 18 months to pore over published stories, consult with experts in India and Nepal, and travel to a variety of regions to speak with residents about their local lore.
Although this journey will be similar to others Alter has made for previous books, it has a different focus: exploring the way in which the same natural event can inspire different stories and traditions. Take the variety of folktales centered on hail, for example. In one story from the Ladakh region of India, often called Little Tibet, a hailstone falls into a womans cup of tea. She swallows it and becomes pregnant, giving birth to a hero who appears in other Tibetan stories. In different parts of the Himalayas, where water from melting hailstones is considered as pure as water from the Ganges, holy men gather hail as part of a purification ritual. The hailstone is a seminal object, says Alter. That its pure and sacred is there in both stories, different as they are in other respects.
When Alter speaks of India, his eyes become bright and his eagerness to return there becomes apparent. He was born in India to Presbyterian missionaries and spent his boyhood in the Himalayan town of Mussoorie, where his family still has a home. Much of his writing deals with the kind of displacement he experienced as a fair-skinned boy growing up in India. Were all sort of straddling one culture or another, he says, adding that MIT has an entire culture unto itself.
Whether or not he returns to the Institute after his travels, Alter knows he has left a mark on his students. I always feel that if they take a creative-writing class, it makes them better physicists, he says. Making up a story taps into different parts of your brain, exercises some of those faculties that dont get exercised in a lab. Alters former thesis advisee Monica Morrison 04 says tapping into her creative side helped her cope with the daily stresses of undergraduate life. It gave me a release, she says. I think that was really important for my sanity. Largely because of Alters encouragement, Morrison, too, ended up straddling two cultures, though in a different way than her teacher had. She double-majored in biology and writing.
10 Breakthrough Technologies 2024
Every year, we look for promising technologies poised to have a real impact on the world. Here are the advances that we think matter most right now.
Scientists are finding signals of long covid in blood. They could lead to new treatments.
Faults in a certain part of the immune system might be at the root of some long covid cases, new research suggests.
AI for everything: 10 Breakthrough Technologies 2024
Generative AI tools like ChatGPT reached mass adoption in record time, and reset the course of an entire industry.
What’s next for AI in 2024
Our writers look at the four hot trends to watch out for this year
Get the latest updates from
MIT Technology Review
Discover special offers, top stories, upcoming events, and more.