There are basically two ways to get through a typical bear market: You can stare at your screen and sweat bullets as the portfolio that-was-going-to-set-you-free melts away. Or you can stare at your screen and cheer as the stocks you missed the first time around slide back to sure-thing, ten-bagger, who-da-thought-it-possible levels.

It all depends on what you own going in. If you're fully invested (or what-the-hell-were-you-thinking margined) in tech stocks, you're pretty much fated to sweat, and you won't find much useful advice here. But if you've got a nice chunk of cash (or bonds, or short positions or bear funds), it's time to start thinking about what you'll buy when things hit bottom.

Image placeholder title

So choose the fields you'd like to ride in the next bull market and get to know them now, before the panic selling starts.

For photonics, of which you will definitely want a piece, see

Jim Seymour's

ongoing

series. As he mentions his favorite companies, add them to a watch list, and study up on this soon-to-be huge field.

Almost as interesting as photonics, believe it or not, is energy, where internal-combustion engines and

Duracells

will soon begin to give way to cleaner, cooler, higher-growth technologies, including:

Fuel cells

, which combine hydrogen (usually) with oxygen to produce heat and water vapor. The basic process has been understood for a century, but the challenge of making it safe and economical is only now, at long last, being met. Look for them to carve out growing niches in cars, home generators and just about anything else where clean energy matters. But see

David Kurapka's

column for some cautionary words on the timing of the transition.

Microturbines

, tiny jet engines that generate nonpolluting power and outlast today's batteries. As you can imagine, there are one or two technical hurdles still to be cleared, but the technology's fans like its chances in products where battery life is crucial.

Flywheels

, where a power source sets a wheel spinning, which then generates energy with its movement. New versions produce plenty of power, last a long time and can come in virtually any size. They'll have a role in fields that rely on uninterrupted power supplies.

For background on fuel cells, see

Wired

magazine's 1997

Hydrogen Economy cover story and

The Hydrogen and Fuel Cell Investor

newsletter (

www.h2fc.com). For flywheels, check out "Re-energizer" in

Wired's

May issue. And for microturbines, subscribe to the online

Wall Street Journal

and search its archives.

Now let's build a watch list. Lots of big tech companies and utilities are into this stuff, but among the emerging players, the following look like good possibilities:

Ballard Power Systems

(BLDP) - Get Report

is a leading maker of fuel cells and related power-generation systems for industrial users. As of last Wednesday, its stock was down 50% from its recent high, though at $5 billion, its market cap is still more than 100 times last year's sales.

Plug Power

(PLUG) - Get Report

makes fuel cells for homes, and will, it says, soon introduce units about the size of a fridge that will power a house without a link to the local power grid. After spiking to 150 in March, its stock is down to around 50.

SatCon Technology

( SATC) makes components and peripheral equipment for fuel cells, microturbines and related things. In other words, it wins if the technologies succeed, regardless of which company ends up selling the actual generators. It's down from 44 to 15 in the past two months.

Mechanical Technology

(MKTY)

is an energy incubator that owns big pieces of Plug Power and SatCon.

DTE Energy

(DTE) - Get Report

owns

Detroit Edison

, as well as a good-sized piece of Plug Power. DTE combines the upside of fuel cells with the safety of a 6.5% yield and single-digit price-to-earnings ratio.

FuelCell Energy

( FCL) has patented a fuel cell that runs on natural gas rather than hydrogen. Its stock is down by more than half since March.

MagneTek

(MAG) - Get Report

makes "digital-electronic power conditioners," which convert the direct current produced by the fuel cells into the alternating current required to run lights and industrial robots.

You'll also want to check out some of the big guys like

United Technologies

, whose

International Fuel Cells

subsidiary does what its name implies, and of course

General Electric

(GE) - Get Report

, which is big in all things relating to power.

Anyhow, now you see why bear markets are so much fun. Great companies get very cheap, and the people able to take advantage of the bargains get very rich. So plug these companies (along with the others that will inevitably come up in the course of your research) into your favorite portfolio tracking service and start getting to know them.

Pay special attention to the ones generating firm orders, since they'll move first when the market turns.

John Rubino, a former equity and bond analyst, is a frequent contributor to Individual Investor, Your Money and Consumers Digest. His first book, Main Street, Not Wall Street, was published by William Morrow in 1998. At time of publication, he had no position in any stocks mentioned. While Rubino cannot provide investment advice or recommendations, he invites your feedback at

rubinoja@yahoo.com.